Flip flops are a casual, easy-to-wear, unisex sandal-type slipper worn casually or leisurely. Flip-flops are stapled trends for beachwear and casualwear during warmer days. Some of us wear flip flops primarily at home, not wanting to go bare feet around the house. Flip flops were derived from the Japanese Zōri when US soldiers brought them back from Japan after WWII. Flip-flops, also known as "thong sandals", dates back to around 4000BC, from Egypt. The ancient Greeks and Romans also wore versions of flip-flops. The late 19th century saw a version of flip-flops known as Havaianas become extremely popular in Brazil.