Rochester Cathedral
If, like me, you have no religious persuasion, Rochester Cathedral is still a great setting for contemplation and perhaps a little melancholy for those no longer with us. Bishop Justus founded the original cathedral in 604AD, while Gundulf (a French monk not to be confused with Gandalf, a fictional character) gave it the Norman look in 1080 after William the Conqueror's succession to rule.
The second oldest cathedral in the country, inside reveals a 14th century Chapter Library door (appointment only which is a shame), John the Baptists fresco dedicated in 2004, a multitude of elegant architecture and an organ of magnitude. Plus, if you still haven't had a big enough history fix, Rochester Castle is literally over the road.