Visit the Paro Dzong, which dominates the valley. Here you will see one of the finest examples of Bhutanese architecture and get a feel for a working monastery that houses hundreds of monks.
The Ta Dzong (National Museum) towers above the Paro Dzong. Viewing its well-interpreted collection of historic artifacts makes for a great introduction to Bhutan culture. Its six floors house ancient and recent paintings, bronze and stone objects, and a four-sided carving that depicts the history of Buddhism.
Just north of Paro is the Kyichu Lhakhang, one of the most sacred temples in Bhutan. Bhutanese history books say that this temple was one of 108 temples built in a single day in 659 AD by Songtsen Gampo of Tibet for the specific purpose of pinning down an ogress who, covering all of Bhutan and Tibet, was impeding the spread of Buddhism in the area. Pilgrims come from all over the region to worship at this sacred site.
At the head of the Paro Valley are the ruins of the once massive Drukgyel Dzong. This fortress sat along a strategic route to Tibet and once provided protection from invasion from the north. From a vantage point on top of the ruins one can see the picturesque Paro Valley below and sacred Jhomolhari Mountain above.
The iconic Taktshang Monastery (Tiger's Nest) is recognizable at first sight as the most famous of Bhutan's monasteries and is a must-see. It clings dramatically to a cliff almost 3,000 feet above the Paro Valley floor. Unfortunately, it suffered great fire damage in 1998 and may only be visited inside with a special permit. However, a small café and a mountainside viewpoint are accessible by a round-trip walk of about four hours. The journey can be made on horseback by prior arrangement.