Canterbury Cathedral

What is it: Canterbury Cathedral was founded in 597, although it was completely rebuilt between 1070 and 1077. In 1170, the bishop Thomas Becket was murdered in the cathedral by four of Henry II's soldiers. This made it a place of pilgrimage, as described by Chaucer in The Canterbury Tales.
What's it like: It's enormous and impressive. Canterbury itself, on the other hand, is small and quaint.
Where: Canterbury, England
When: I cannot remember for the life of me.
How: We went to Canterbury for a weekend - went down by train on Saturday morning and came back Sunday.
Worth noting: Thomas Becket's bones were destroyed by Henry VIII in 1538 who also unsainted him. 
Place in the 2015 edition: 219
Does it deserve to lose its place in the top 500: No - so much history!