Isidor and Ida Straus are the first people we've profiled who became millionaires during their lifetimes. According to a New York Times article published after their tragic deaths, the couple had a combined fortune of $3.8 million – the equivalent of around $110 million (£86m) today – thanks to their involvement with Macy's department store in New York.

With a background in crockery, Isidor had opened the glass and china department at Macy's. By 1896, he and his brother Nathan were the sole owners of the iconic store. Isidor also served a one-year stint as a US Congressman.