Mental Floss (stylized mental_floss) is an American digital, print, and e-commerce media company focused on millennials. It is owned by Dennis Publishing and based in New York City. mental floss, which presents facts, puzzles, and trivia with a humorous tone, draws 20.5 million unique users a month. Its YouTube channel produces three weekly series and has 1.3 million subscribers. The magazine mental_floss has a circulation of 160,000 and publishes six issues a year. In October 2015, Mental Floss teamed with the National Geographic Channel for its first televised special, Brain Surgery Live with mental_floss, the first brain surgery ever broadcast live