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.
Southwark Cathedral, London, by Steve Thompson. (or The Cathedral and Collegiate Church of St Saviour and St Mary Overie) lies on the south bank of the River Thames close to London Bridge, it is the mother church of the Anglican Diocese of Southwark, and it has been a place of Christian worship for over 1,000 years. Built in 1106