AdvertisementReading A Letter That's Been Sealed For More Than 300 Years — Without Opening ItMarch 02, 2021Nell GreenfieldboycefacebookEmailA computer-generated unfolding sequence of sealed letter DB-1538. New research describes how "virtual unfolding" was used to read the contents of sealed letter packets from 17th century Europe without physically opening them. (Unlocking History Research Group)