Or is it a castle at all?
Old abandoned tunnel near Holborn tube.
The biggest, best, and most bizarre.
What lies behind London's most-used pedestrian bridge?
Shining a light on London's least used bridge.
Open to visitors every Wednesday.
From lurking monks to those mysterious red pillars.
Buried, but not yet forgotten.
Even includes urine deflectors.
See the Good Morning Britain desk and the This Morning sofa.
Clandestine cake encounters.
How many of these have you leapfrogged?
For lovers of old school tech.
London: 101 Oddities by J Edward Hart.
Four centuries of historical tidbits.
Some are still open to visit.
Exhibition looks at vanished waterways.
Unseen London is back.
Dogs and canoes - sadly not together.
We went to the top.
We've just made Christmas bearable.
Backstage and behind the scenes at London's theatres and museums.
Nobody knows where...it's a secret.
Abandoned station opens in June. Tickets on sale Monday.
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