The Royal Botanic Gardens at Kew is an enormous repository of plant life that also happens to be highly tourist-friendly. The most recognizable site is probably the Palm House (shown here). It was the very last thing we saw after a long (6 hour!) visit to the gardens.
We started in a quiet corner at the south end of the gardens because there was an enormous queue at the entrance closest to the tube station. It was April so quite a lot was blooming, including this large field of tulips.
The treetop walk is supposed to let you see the canopy of the trees up close. It's a bit contrived since this isn't exactly the rainforest but it's still a good view of the surrounding gardens. The walkway is not solid and it's probably not a great place to go if you have a fear of heights. If you don't have a fear of heights, it's a good place to watch other people have a fear of heights.
Most of Kew is just gardens, like you may expect from a Botanical Gardens. There are miles of trails and just about every type of garden you might be looking for. These are Monkey Puzzle trees which are probably not easy to find in England outside of Kew.
The playground is a good place to rest in the middle of a garden tour. Well, for the adults at least. There is also a restaurant and ice cream shop here. Most importantly, they serve beer and cider while you're lounging on the grass resting in the middle of your visit.
There is a small palace along the Thames river (Kew Palace) which started this whole thing off. You can visit a few rooms inside and there's a small formal garden adjoining the river.
This is the Hive. It's an art installation within Kew Gardens. It's rather prominent from some distance away and close-up it's actually even more impressive. It's sort of vaguely representative of a beehive.
Inside you can stand on the bottom level and take pictures up through the transparent middle level like this. Yay.