The British Library!
Sadly, no photos are allowed inside, so you'll just to imagine us peering into the dimly-lit glass cases to see treasures such as the Magna Carter(!), Beethoven's tuning fork (!!), and an original and only partially burned Beowulf manuscript (!!!).
I also paid homage at the First Folio on display, the second one I've seen this year thanks to the DC trip earlier this spring.
We're at a pub now, waiting for lunch and enjoying their ridiculously fast wifi.
Only seven more hours until we get to go to sleep! Whoo!