All about slots: History, Types, Themes & Symbols

… and which are the Top 10 most popular slots

Slots are one of the most popular casino games in the world, attracting huge crowds of people to physical and online casinos. Unlike the other casino games such as blackjack or poker, playing slots is much easier, mainly because players do not need to have previous experience.

The word "slot machine" comes from the Greek word "automatos" as it is used for technical devices or machines whose initial impulse performs independently and reliably predetermined activities without requiring direct interaction with humans. The slot machine is essentially a device that operates a game, both for fun and to potentially make money. Terms that are synonymous with a slot machine differ slightly based on the terminology used in different countries. These include: Slot Machine, Slot, Slots, Fruit Machine, Poker Machine, Pug, Pokita. All of these are some of the names slots are called.

When were the slots created?

The story of the first slots starts back in the 19th century. The first slot machine was constructed in 1891 by Sitman & Pete in Brooklyn, New York. There was a handle which was used to operate the machine. The machine itself used a system of symbols and disks. The player knew he won by a special combinations of symbols. These machines had 5 reels, each with 10 cards. At those times, there were no direct winnings and rewards were in the form of food, drinks or services.

The first slot with similar functions as today’s slots was created in 1985 by Charles Faye. Its name was Liberty Bell. It used 5 types of symbols – bell, diamond, horseshoe, spade and bowl – and had 3 reels. The machine offered cash prizes after each win. The machine became hugely popular and of course, imitations were created. The next famous slot machine to be created was Operator Bell. It was created by Herbart Mills in 1907. Operator Bell is considered one of the pioneers in the slot machines world. Today these two machines can be observed at Nevada State Museum.

The massive spread of slot machines

The first electro-mechanical slot machine was called Money Honey and was created by a company called Bali in 1963; it could pay up to 500 coins without the intervention of an operator. The popularity of slot machines started spreading worldwide.

Significant changes and innovations in the world of slot machines occurred with the oncoming of video game machines. The first video slot machine was invented in 1976 by Fortune Coyne. Its first live test took place in Las Vegas, the Hilton Hotel. The entire company along with its video slot machine technology was purchased by International Gaming Technology (IGT) in 1978. After that, the first slot machine offering a second screen showing a bonus reel appeared in Australia in 1994. In the United States, it was made by WMS Industries in 1996. The second screen allows players to access a bonus game that offers additional winnings.

How do slots work?

Many people believe that the huge popularity of slots is due to their simplicity, which makes them a very good choice for players who are not experienced. Unlike poker or blackjack games which require skills, in slots you need mostly luck.

In terms of the way they work, slots are much more complex than playing poker, as they use extremely complex computer algorithms. Before players start betting, it would be good to learn the most basic things about slots, as this way they will have a better chance of winning. But is this even possible? The answer is yes.

The way the slots work is quite simple. Unlike other casino games in which players face a croupier or other players, you face a machine or a computer. Classic slots have handles and a reel, on which symbols such as cherries, plums, oranges and bar symbols most often appear.

To start playing you need to place a coin, or if you play online, place your bet by selecting your preferred paylines. Winning lines are positions on the reel where certain symbols must appear in order to win. When playing video slots, there is a special button with which you will be able to choose how many of the winning lines to activate. Whether you play online or prefer to gamble at a land based casino, the reels will start spinning as soon as you start playing. Whether you win or lose depends only on the new symbols that appear on the reel, and on their location. The goal is to collect identical symbols on the paylines. The biggest winnings or jackpots are given when you see a rare combination of symbols and if you have made the biggest possible bet.

The first slots had maximum of 5 winning lines, while today you can find slots that have hundreds of winning lines. The more paylines the slot has, the better your chances of winning. The payout that players will receive depends on the table of winning symbols and combinations, and some of the most important things to keep in mind are the amount you bet and the number of identical symbols that appear at the same time. It is especially important to understand the slot you are currently playing, as each slot is unique and there are thousands of games to choose from.

One of the main things you need to know when learning to bet on slots is that the outcome of each game is determined by a complex device called a random number generator. This ensures that the chance to collect the necessary symbols to win will remain the same and you can play for days or weeks without winning the jackpot. If luck is on your side, you can win two or even three times in a row.


The Random Number Generator (RNG) is the basis of standard modern slots. The random number generator is a microprocessor and is similar to those used in computers. This microprocessor creates random sequences of numbers and these numbers can reach up to a thousand per second.

The random number generators can be two types – real and pseudo RNGs /in these the number sequences are generated by different computer algorithms. In the pseudo RNGs, the results are determined by a given value or key which means that if you know this value, you can predict and manipulate the results. Pseudo RNGs are often used in electronic games or cryptography and their results are as random as possible. The results cannot be reproduced or manipulated in any way if you do not have the initial value.

Another important thing to keep in mind when considering playing slots is the RTP %. This percentage shows how much of the bets that players made on a particular slot will be distributed as winnings. This percentage varies in different slots – for example, for video slots it can be 90% but for some other slots it can reach above 95%. On the other hand, the house edge, which is the advantage of the casino, is opposite of RTP – so if the RTP of the slots is 96%, the house edge will be 4%.

What about bets and paylines?

One of the most important features in slots is the number of paylines – these are the reel positions where the symbols appear – and then allowing you to win. The first slots had only one payline running in the middle of the reel. The player usually wins when he gets 3 identical symbols positioned simultaneously in a line. Nowadays, slots have many pay lines and their shapes vary – some are V-shaped, some have a zigzag shape, even there are shapes that resemble an inverted V. Usually, slots have pay lines ranging from 5 to 10 but there are slots with pay lines going up to a 100.

When identical symbols arrange from left to right, you win. Also, there are many slots now in which the combinations that win appear in both directions. Such slots are extremely popular as they give you the chance to win twice. Another popular slot feature is a system called Both Ways. In such slots, there are no pay lines and players can win for every possible combination of symbols. What is so special about these kind of slots is the format and the ways players win – for example, in some of these slots the winning combinations can be formed in different number of ways – 243, 720, 1024 and up to 3125 ways.

And what can we say about bets? The new slots et players choose the values of the betted coins and the amount they want to bet. In some slots, bets can start from £0.01 /these are called “penny slots”/. The value of coins can reach £1 and even much more. The bet amount depends on the denomination you choose, the number of pay lines that are active and the number of coins you want to bet.

The slots also offer another interesting option called Max Bet – this option allow player to bet on all pay lines with the biggest possible bet. For some slots this is the only way to win a jackpot but this means also the possibility of losing a large amount of money.

Slot types

Classic slots

The classic slots consist of three reels and only one payline, which makes the winning spins small in number, but the winnings - relatively large. In online casinos you will come across many classic slots, which are on the same basis, but with different symbols. The most common symbols are single, double and triple Bars, horseshoes and diamonds.

Video slots

Although many players like classic slots, video slots are becoming more popular because of their captivating themes, 3D graphics and beautiful images.

Video slots can be inspired by famous books, movies or series. Quite often such slots become popular among players almost immediately. When creating their unique slots, software companies also draw inspiration from historical periods, fairy tales and mythology, thus bringing them closer to video games than to classic slots. Different bonus games, as well as games in which you have to show your skills are intertwined with various intriguing plots. Undoubtedly, the captivating audio effects as well as the complex animations will help slot lovers to fully immerse themselves in the game.

Slots with multiple winning lines

Many slots offers a various number of winning lines to distinguish themselves from each other. Slots with 3, 5, 9, 15, 20 or 25 paylines are most common, but there are slots that have 243 or 1024 paylines.

Megaways slots

The most popular slots in online casinos are those that come in the form of Megaways. What does this mean? Megaways slots on each spin randomly choose the different number of winning combinations that you can get, even up to 100,000. The winnings of this type of slot machines can sometimes be huge.

Bonus slots

Bonus slots are probably the most popular in online casinos, for the simple reason that a bonus can bring you huge profits. Bonuses are most often free spins, a different function or a doubling. Some online slots even offer combinations of these types of bonuses.

  • ---- Bonus Function - These bonuses most often bring you direct cash prize.
  • ---- Free spins – Often you receive free spins when you get three or more scatter symbols. Then you win a number of free spins, in which you can often find an additional multiplier or more wild symbols.

Fruit slots

Fruit-themed slots are among the most favorite and preferred offers in any online casino. Most of them do not have the option to win a bonus or free spins, but often have different features. For example, many fruit slots have a Wild symbol that stretches and occupies the entire reel on which it fell. There are even wild symbols that stretch to two reels.

Jackpot slots

These slots can bring the biggest profits. As with any other slot, it is all about luck, as the jackpot amounts are won at random.

Progressive jackpot

It is the progressive jackpots that can make an online casino customer who bets the minimum amount on a slot game a millionaire. These jackpots increase the value of their levels with each spin that someone makes on them. When a jackpot level is won, it returns to the starting position, with the value preset by the slot provider. Progressive jackpots are again won at random, and very often there is a bonus associated with them, that determines which exact level of the jackpot you will win.

Slot themes

Some of the most popular slot themes are:


As the name suggests, these slots are filled with animal symbols that can be from any part of the globe.


undoubtedly some of the most popular slots out there. These slots have symbols such as pharaohs, pyramids and many other Egyptian symbols


Many of the slots are based on the well-known fairy tales, and you can find games with themes like Little Red Riding Hood, Puss in boots, Snow White and many more.


Many popular movies and series have been turned into slot games.


Another popular theme is history, and you can find slots with symbols from the recent or distant past, such as the era of dinosaurs, Mayans or Vikings.


Many slots feature pirates and treasuresq dmother onteresting slot theme.

Slot tournaments

A number of online casinos offer attractive slot tournaments that make their customers gamble even more in the casino. These tournaments most often reward participants based on their bets. The prizes in the slot tournaments are also quite attractive, but winning them is not easy at all, because a lot of casino customers take part. However, with the right strategy and a well-thought-out choice of game, it is very likely that you can win.

Which are the most popular slot symbols?

A number of online casinos offer attractive slot tournaments that make their customers gamble even more in the casino. These tournaments most often reward participants based on their bets. The prizes in the slot tournaments are also quite attractive, but winning them is not easy at all, because a lot of casino customers take part. However, with the right strategy and a well-thought-out choice of game, it is very likely that you can win.

Scatter symbols

Scatter symbols are type of a symbol that most video slots have. Most players look for slots with such symbols, as they give the biggest winnings. Scatter symbols are quite different, as each game can have its own unique special symbols. What makes them really interesting is that they don't have to appear in a specific position on the reels or in a specific sequence for the player to win. In most cases, when the player gets two or more Scatter symbols, there are bonus and free games activated. In some games the Scatter symbols helps you increase you winnings and in other games you win when you get three Scatter symbols.

Wild symbols

Wild symbols can replace all other symbols, which helps you win big. For example, if you get two identical symbols and a Wild symbol, you will receive a payout that is given for three identical symbols. When you get two or three Wild symbols, your winnings go up.

In many games, the Wild symbols can increase your profit, award you with free games or activate bonus games.

Which are some of the special slot options?

Free games

Most of the slots give players free games, which can be activated in different ways. Most often free games are given when you get 3 Scatter symbols.

Bonus Games

Most often, what makes slots so exciting are the bonus games. They can be activated in different ways, and in most cases this happens when you get 3 special symbols /Scatter or Wild/ or when you have activated all the paylines. However, before you place your bet, you should always check the table of winning symbols and combinations..


Most common in free spins, multiplier symbols increase the amount of each win in which they participate, while also playing the part of a Wild symbol. They can make each of your winnings up to 10 times higher, offering even multipliers that multiply by themselves

Top 10 most popular slots

Book of Dead

RTP 96.21%

Provider: Play'n GO

Theme: Ancient Egyptian

Reels: 5, Pay lines: 10

Age of Gods

RTP 94.03%

Provider: Playtech

Theme: Greek Gods

Reels: 5, Pay lines: 20

Mega Fortune

RTP 96.6 %

Provider: Netent

Theme: Luxury, Money

Reels: 5, Pay lines: 25


RTP 94.1 %

Provider: Playtech

Theme: Gladiators

Reels: 5, Pay lines: 25

Game of thrones

RTP 94.86 %

Provider: Microgaming

Theme: TV show & Movies

Reels: 5, Pay lines: 243

Gonzo’s Quest

RTP 96 %

Provider: NetEnt

Theme: Fantasy

Reels: 5, Pay lines: 20

Mega Moolah

RTP 88.12 %

Provider: Microgaming

Theme: African Safari

Reels: 5, Pay lines: 15

Goblins Cave

RTP 99.32 %

Provider: Playtech

Theme: Fantasy

Reels: 3, Pay lines: 3


RTP 96.01 %

Provider: NetEnt

Theme: Jewels

Reels: 5, Pay lines: 10


RTP 95.07 %

Provider: IGT

Theme: Egyptian

Reels: 5, Pay lines: 20