Automatic doors, a 2,000-year-old invention

Several years ago, I happened to visit the plantation of former President Thomas Jefferson in Monticello, Virginia, USA. His estate which was completed in 1809 boosted on having a set of automatic doors inside the parlor. I found this a fascinating feature since I assumed this kind of automation was only born in the second half of the 20^th century. Well, I was wrong. 

Hero, a Greek engineer and mathematician from the 1^st century AD is the oldest known - or documented - inventor of the automatic door. The working principle is simple and must have amazed those who witnessed how the temple doors would open ‘spontaneously’ after the prayers of the priest.

We keep forgetting the huge amount of knowledge that was circulating in antiquity. Most of the great minds performed in many fields. They were philosophers, astronomers, mathematicians, architects, engineers, geographers, poets, etc. (see: Greek philosophers Alexander knew).

What a wondrous world!