St Paul's was designed by Christopher Wren and built after the Great Fire of London in 1666. It's the third or fourth cathedral to be built on the same spot. This picture shows the dome and is taken from the River Thames.
The interior (no photography allowed) was redesigned during the Victorian era, because Queen V. was bored with Wren's plain white walls. It's very ornate, all gilt and gold and beautiful lighting. The whole thing is a combination of Cathedral, Museum, and Crypt.
This picture shows the Cathedral from the street entrance side.
The Cathedral was saved from Nazi bombing during WWII by a volunteer fire brigade who stood on the roof during the raids (!) and bucketed out fires the bombs caused. There is a lovely chapel to honor American Armed Services personnel who helped to save Britain.
After a tour led by a very knowledgeable verger, we returned to hear Evensong services sung by the St Paul's choir boys and priests. The acoustics were amazing, wonderful organ music. It's quite something that such a concert takes place every morning and evening, twice on Sunday!