Operated by and just across the road from the National Museum of Natural Science, Taichung Botanical Garden (台中植物園) boasts 700-plus species of plants and trees spread over 4.5 hectares.
The outdoor section is pleasant, but the main attraction is the Tropical Rainforest Greenhouse, a steel-framed dome 31m high and 56m in diameter. The dome, which contains its own waterfall and creek as well as 300-plus plant species, is said to be the largest of its kind in Asia. It's easy to spend an hour or more inside.
In the greenhouse's basement there is an aquarium with some strikingly huge fish from the Amazon, plus a number of tiny, extremely colorful and exceptionally poisonous frogs.
From the National Museum of Natural Science, cross Xitun Road and you'll be in the Botanical Garden.