Last year, Americans spent $2.6 billion on arguably the most popular shoe of summertime – the flip-flop.
“They are probably the oldest form of footwear,” said Tamera Lyndsay, founder of The Shoe College in Arizona.
Flip-flops date back to ancient Egypt, around 4000 B.C, Lyndsay said. But multiple cultures have put their own twist on the sandals. For example, instead of placing the strap after the first big toe, “the Romans used the second toe, the Mesopotamians the third toe,” she said.