This weekend it’s open house weekend, lots of government buildings are open for free.

Quote:
“Londoners are given direct access to the teams that design, construct, conserve and regenerate their environment. Alongside this are special programmes, activities and publications.”
http://www.openhouse.org.uk/london/home.html

Here’s London from the top of the Gherkin last year

Unfortunately I think I’ve seen most of the good stuff now, and there’s lots of queuing (lines).

This is the que/line at the bank of England last year

the bus stop is the 1.5 hour mark.