Fortress, palace and prison—the Tower of London has filled all these roles and more during its nearly thousand year lifespan http://on.natgeo.com/2GFkUhI

Fortress, palace and prison—the Tower of London has filled all these roles and more during its nearly thousand year lifespan http://on.natgeo.com/2GFkUhI 

https://twitter.com/NatGeoTravel/status/967383652320628736