Koishikawa Botanical Gardens, a park owned by the Graduate School of Science, The University of Tokyo. The park itself is surprisingly vast and just under-the-radar enough that you can take a walk around the forest-like sections without feeling like half of Tokyo has come along with you.
There is also a Japanese garden section, perfect for picnics. This used to be the University of Tokyo's Medical School building. It is now a museum, and from what I could see from the outside, it houses a number of animal skeletons.
The greenhouse is almost hilariously neglected. You can imagine it being used for research, but clearly no-one has given any thought to making it appealing for visitors.
The only surviving portion of a Chinese medicine tree. If I remember correctly, the tree was split when it was struck by lightning.
Slightly maze-like paths leading to the "forest".
A small shrine in the middle of the park.
An ibis isn't necessarily an indication of
abundant nature, but you do feel as though you've stepped out of the city when you see one.
It was catching bugs one after another.