Although today, chocolate comes in all shapes and sizes, we have only been eating it in its solid form for about 160 years.
Prior to this, chocolate was mixed with water and spices and poured between two containers to make a frothy drink.
Chocolate is made from the pods of the cacao tree, which is native to Southern and Central America.
It was first discovered in 600BC, by the Olmec people of Mexico, who left the cacao beans in tombs, believing that it would energise the soul and help their transition to God.
About a thousand years later, the Aztecs and Mayans served chocolate drinks at feasts, weddings and birth ceremonies. They made the drinks by firstly fermenting the cacao beans and drying them in the sun. Then they removed the outer shell and ground the inner nibs to a paste, which was then mixed with hot water and spices.
Although this drink was bitter, the Aztec ruler, Montezuma drank several litres of it a day, believing it was good for building up resistance and fighting fatigue.
When the Spanish conquered the Aztec empire, they exported the chocolate beans to Spain. However, they did not like the better taste of the drink and so it was originally used solely as a medicinal product. After a while they added sugar, which greatly improved its taste and very soon, it became a luxury chocolate beverage to be consumed by the elite.
The desire for the sweetened chocolate drinks spread throughout Europe, leading to the first chocolate house being opened, in London, in 1657.
As the demand grew, the British, Dutch and the French introduced cacao tree plantations into their colonies. Soon after, thousands of people were enslaved for the purpose of manufacturing chocolate.
Once the supply of chocolate increased, it became more affordable and efforts to process it increased. In the early 1800s, a Dutch man called Coenraad Van Houten, designed a cocoa press to extract the cocoa butter from the ground nibs and a method for washing the cocoa in alkali solution so that it was more soluble in water.
In the 1850s, an Englishman called Joseph Fry added cocoa butter to the chocolate powder rather than water, producing the first bar of chocolate.
Soon after, in 1875, Henri and Peter Nestle added condensed milk to the chocolate powder and cocoa butter, producing the first milk chocolate bar.