Halong Bay is one of Vietnam's top attractions, but it's also incredibly crowded. If you're looking for a less touristy experience, consider this 2-day cruise from Halong Bay to Bai Tu Long Bay. Highlights of the trip include the floating Vung Vieng Fishing Village and Pearl Farm, as well as the Thien Cahn Son Cave. Onboard, you can enjoy activities like tai chi and a cooking class.