Automatic door

Automatic doors were invented in ancient Greece to assist the polytheistic society. As there were many Gods in Greece, the priests and other religious figures for each God had to come up with new ways to keep the masses coming with offerings. To this end, they created automatic doors that were placed within the altar at the place of worship.

When a person made an offering to one of the Gods, the doors of the altar opened, thanks to a fire being ignited within the altar. This same idea was used to move statues within the place of worship.

It is believed that Heron of Alexandria designed the first of automatic doors, which worked via compressed air or water. Evidence also exists that when someone lit the fire within the altar a thin rain of flavoured water would pour down upon those attending the religious event in the temple.