Lincoln Cathedral, England, one of Britains finest ecclastical buildings. Originally built between 1072 and 1092 by Bishop Remigius de Fécamp, it became the mother church of the Diocese of Lincoln and was once the tallest building in the world after its central spire was added in 1311—surpassing the Great Pyramid of Giza—before the spire collapsed in 1548! It also sits on a hill which makes it even more impressive.
Lincoln Cathedral holds one of the four surviving original copies of the Magna Carta (on display at Lincoln Castle), serves as a memorial to WWII aircrew, and features regularly in film and media such as The Da Vinci Code and The Young Victoria.
 
Interesting facts...
There are so many but perhaps the biggest one is the amount of hidden things to find in the cathedral. Symbols, Graffiti, little sculptures and even stone selfies all hidden around the cathedral by mischievous workman.