Visited the California Academy of Sciences while in San Francisco and really enjoyed it. There is much more to see than I expected, so I would recommend setting aside at least 3 hours.The aquarium was my favourite part, with a good variety of marine life and well-presented exhibits. The rainforest dome was also interesting, with tropical plants, butterflies and birds flying around as you walk through the different levels. It really does feel like stepping into a rainforest.The planetarium is worth visiting too, but check the show timings when you arrive. I also liked the Living Roof, which is quite unique and worth a look.It can get crowded, especially around the aquarium and rainforest. Tickets are quite expensive, but you are getting an aquarium, rainforest, planetarium and natural history museum all in one place. Overall, a great place for both teenagers and adults, especially if you enjoy science, animals and nature.