- The White Tower is built mainly of Caen Stone and Kentish
Ragstone and was originally whitewashed.
- The Crown Jewels contain the oldest stones in the Tower;
the diamonds were formed three billion years ago.
- St Thomas's Tower and Traitor's Gate: restored with interlocking
blocks of Kentish ragstone above the original Caen Stone
- Beauchamp Tower: inside, the Caen Stone walls have been
carved by desperate prisoners captured by the Tudors.
- Bloody Tower: the left-hand gate shows honey-coloured
and cross- bedded oolitic limestone.
- Middle and Byward Towers: massive, pale buff Caen Stone
at the base, with upper levels of white Portland Stone.
Learn more about The Tower of London's
building stones in the Holiday Geology Guide available from the BGS Bookshop.