The American Museum of Natural History is well known for Night at the Museum. The animal exhibits are like a scene cut out of a living thing, so you never get bored of looking at them. It would take a day to see everything, but if you just want to see the main attractions quickly, you should be able to do it in about 2 hours. In fact, that's the limit if you have children. I went around 3:30 in the afternoon, and there were not many people, so I was able to go around comfortably. After purchasing the ticket on Klook, I was told that I needed to make a separate reservation to enter, but when I went, I was able to enter with just the QR code on my Klook voucher.