You can't really go to Bhutan without hiking up Tiger's Nest (Paro Taktsang). A temple built into a mountain cliff where Guru Rinpoche (aka Padmasambhava, the guy who brought Buddhism to Bhutan) supposedly meditated in a cave for 3 months during the 8th century. So, why is it called Tiger's Nest? Well the two legends are as follows.
"Taktsang which literally means "Tiger's lair", it is believed that Padmasambhava (Guru Rinpoche) flew to this location from Tibet on the back of a tigress from Khenpajong. This place was consecrated to tame the Tiger demon. An alternative legend holds that a former wife of an emperor, known as Yeshe Tsogyal, willingly became a disciple of Guru Rinpoche (Padmasambahva) in Tibet. She transformed herself into a tigress and carried the Guru on her back from Tibet to the present location of the Taktsang in Bhutan."
Regardless of the storied origins, the main temple is very impressive. The hike isn't too hard, though the high altitude does make it harder than if it was in SE Asia or the States. I hiked it in the traditional dress of the Bhutanese men as a way to maybe connect more with the hike, temple and grounds around me.