Founded in 1621, the classic 17th-century walled garden is the oldest in Great Britain. Funny fact: when they built it, they spent so much on the wall... that they had little left to buy the actual plants! I fell in love with the garden's black pine tree that was planted in 1800, making it the oldest specimen of the species in Britain. Apparently J.R.R. Tolkein was a fan of this magnificent tree, too.
THEN, you'd never believe what they have growing in one of their glass houses.... This -->
It's a Victoria lilly, and it looks positively prehistoric — don't you think?!
For more on the history of the garden: http://www.botanic-garden.ox.ac.uk/history-botanic-garden