As a not-so-secret floral enthusiast (see here, here, and here), the Royal Botanic Kew Gardens was one of the first destinations off my list during my first few weeks in London. A sprawling 300 acre property, Kew Gardens was originally the "backyard" of Kew Palace, the eventual secluded home of Mad King George III during his various bouts of insanity. Today, Kew Gardens is one of England's leading botanic research centers with several climate controlled greenhouses (the Palm House has a spiraling staircase you can climb to get an aerial view of the tropical palm trees), an art gallery, Chinese pagoda, and a treetop canopy walkway 18 meters above the ground. It's the perfect place to immerse yourself in a little history, fresh air, and beautiful flora.
Where: Kew Gardens
You can take the District Line on the Tube!
When: All-year round
Tyro Tip: During the holidays, they have illuminated light shows after sunset, a North Pole village, and scented Fire Garden. I'm already planning a return trip. ;-)