The Golden Hinde is truly a hidden gem in London. It's a full-sized, still sailable reconstruction of the original ship with which Francis Drake sailed. This replica was launched in 1973 and since they sailed for more than 140000 miles.
John Marshall founder of Marshall's Charity lived at his mansion house near this spot until his death in 1631 as did his father before him. Marshall's Charity had its offices here until 1967 and now has a more modern building across the road. The building is now owned by Guys Hospital. There are lots of interesting little statue heads all over it.
Did you know that the Millenium Bridge was the first bridge to be built over the Thames after the Tower Bridge had opened in 1894? It's a lovely pedestrian bridge, unfortunately the dementors destroyed it in Harry Potter!