The Annapurna trek is longer and takes 12 to 21 days, featuring a wide range of landscapes and crossing a high pass called Thorong La. It offers views of the Annapurna mountain range. The Langtang trek is shorter, usually 7 to 10 days, and focuses on the Langtang Valley with its beautiful, lush scenery and views of the Langtang Himal range.