Bread and butter pickles

A pickled cucumber – commonly known as a pickle in the United States and Canada and a gherkin in Britain, Ireland, South Africa, Australia, and New Zealand – is a usually small or miniature cucumber that has been pickled in a brine, vinegar, or other solution and left to ferment. The fermentation process is executed either by immersing the cucumbers in an acidic solution or through souring by lacto-fermentation. Pickled cucumbers are often part of mixed pickles. It is often claimed that pickled cucumbers were first developed for workers building the Great Wall of China, though another hypothesis is that they were first made as early as 2030 BC in the Tigris Valley of Mesopotamia, using cucumbers brought originally from India.

Source: Wikipedia