There are plenty of waterfalls around Chiang Mai. Sometimes they’re a bit boring because of the dry season, and sometimes too intense during the rainy season. What makes the Sticky Waterfalls special is that you can climb up barefoot from bottom to top. The rocks aren’t slippery, but... sticky. It’s a bit of a tourist trap, but you can take great photos for your Instagram and spend about an hour there. Entry is free, but you need to register upon arrival. Swimwear is allowed, but you can also climb up fully clothed.
How to get there: there aren’t really organized tours to the Sticky Waterfalls, but if you stay in a hostel, they often organize a red taxi a few times a week that takes a group there, waits, and brings you back. Sometimes the Sticky Waterfalls are part of a day tour offered by a tour operator. If you gather a few people, you can also book a red taxi yourself. Expect to pay around 500-800 THB for a round trip.
You can also get there by scooter (but first read the text about traffic and renting a scooter in Chiang Mai): if you do, follow the walking route to the Sticky Waterfalls on Google Maps. The first 10 km are still within Chiang Mai’s urban area, but after that the road gets quieter and eventually takes you through forests and past lakes. This way you avoid the main highway to the Sticky Waterfalls. Only ignore the last few kilometers of walking instructions, because Google literally sends you into the forest — so always stay on the paved road.