It's one of the most basic items in your closet, but it has a long history. The name "flip flop" comes specifically from the sound the sandals make when they slap between the sole of your foot and the floor.

This particular type of sandal originated as early as the Ancient Egyptians in 4000 BC, and the oldest known pair is on display at the British Museum from 1500 BC. This pair is made from papyrus, but just as a huge variety of cultures have worn these sandals through the years, they've used a great variety of materials.

Papyrus and palm leaves were the most common materials used in Ancient Egypt, while rawhide was the material of choice among the Masai of Africa. In India, these sandals were mostly made with wood, and many used rice straw in China and Japan. Of course, in modern times, most cultures have moved to leather, rubber and other sturdier textiles.

What we know of as the modern flip flop gained popularity in the United States after the end of World War II. They are derived from the Japanese zōri, which soldiers brought back to the States with them. During the postwar boom, Americans started to design flip flops in new bright colors and patterns, wearing them for their convenience and comfort. In the 1960s, they became primarily known as a part of the casual beach lifestyle of California.

Havaianas, a classic and well-known brand, was created in 1962 in Brazil by the country's largest footwear brand Alpargatas. By 2010, more than 150 million pairs of the sandals were being produced per year. Rainbow Sandals -- a favorite for many -- were created in a garage in Laguna Beach, CA during the early 1970s, and have become well known as a dependable pair that doesn't wear down easily. They are now offered in a variety of styles, and the company produces over 2 million pairs every year.

Flip flops are a popular choice among people of all ages, typically worn in casual settings. Younger generations tend to feel it's okay to wear them to formal events, while older generations reportedly feel this is a sign of laziness and choosing comfort over style. We have to agree that basic flops shouldn't be worn to fancy events, but we've seen some pretty stylish (and bedazzled) styles that can definitely be considered "dressed up."

Whether you're wearing a pair of classic rubber flops or a leather pair with pretty detailing, you know the necessity of these sandals for every individual's wardrobe. Click through the gallery above to see a history of flip flops in photographs!