This is St. Paul's cathedral. The cathedral was designed by Christopher Wren to be re-built after the Great Fire of London in 1666. Even if you are not particularly religious, you can still go and view the beauty of the cathedral.
This beautiful building in Fleet Street, known as "Prince Henry's Room", managed to escape the ravages of the fire. Once a tavern where Samuel Pepys liked to cavort, its intricately decorated plaster Jacobean ceiling is one of its most impressive features.