Crossing the Black Mountains which separate western and central Bhutan, you'll enter a part of the country which until the 1970's was only reached by mule and foot trails. The mountain road passes through deciduous forests and at the second pass, Pele La (3300m), the entire area is blanketed by high altitude dwarf bamboo. About five miles from Tongsa, the road winds around a cliff and takes a sharp turn to the left. The view is one of the most beautiful sights in all Bhutan and one from which you will never tire. Sloping down the contour of a ridge stands the many-leveled Tongsa Dzong , built in 1648.
Tongsa is the biggest dzong in Bhutan. It is located at a very strategic position. The view from the dzong extends for many kilometers and in former times nothing could escape the vigilance of its watchmen. Furthermore, the dzong is built in such a way that in the old days, no matter what direction a traveler came from, he/she was obliged to pass by the Dzong. This helped to augment its importance as it thus had complete control over all east-west traffic. That's why Tongsa Dzong is sometimes called "The Door to Eastern Bhutan".