Designed by Christopher Wren in 1669, it took less than 30 years to build this symbol of London. I believe this is the only cathedral in GB that has a dome, which is one of the largest in the world.
I finally got to visit this majestic structure with my parents. In December the upper galleries/balconies, that can be seen from outside, will be open, please visit if you have a chance.
Also a fun fact, I hope it's true: apparently the architect had to redesign the building several times, as his proposal with the dome would not get accepted. He finally handed in the design with the tower that got approved, with a small writing: "the architect is allowed to make small alterations to design." And voila, London's skyline has got a dome!
St. Paul's Cathedral