What makes tattoos permanent?

The earliest recorded tattoo was found on a Peruvian mummy in 6,000 BC. That's some old ink! And considering humans lose roughly 40,000 skin cells per hour, how do these markings last? Claudia Aguirre details the different methods, machines and macrophages (you'll see) that go into making tattoos stand the test of time. [Directed by TOGETHER, narrated by Addison Anderson].