Experts cracked the 4-letter code on a 400-year-old shipwreck padlock

A brass padlock from 1583, found by a metal detectorist near Margam in Port Talbot back in 1999, has finally been opened using modern scanning to figure out the four-letter combination. I love that combination locks existed in this form in the 16th century at all. It makes you wonder what the owner was protecting and how often they forgot their own code. What's the most surprisingly 'modern' everyday object you've seen from the past?