Beihai Park covers an area of about 0.71 sq km (about 0.27 sq miles), more than half of which is taken up by the lake. In the middle of the lake and on the central axis of the whole park lies the Jade Flowery Islet, topped by the imposing White Dagoba (pagoda) which is the landmark of Beihai Park.

On top of the Jade Flowery Islet, the White Dagoba was built in 1651 on the former site of the Palace in the Moon where Kublai Khan received Marco Polo. At the suggestion of a famous Tibetan lama, Emperor Shunzhi, the first emperor of the Qing Dynasty agreed to build such a Tibetan dagoba to show his belief in Buddhism and his desire for the unification among various Chinese ethnic groups. The White Dagoba was destroyed in an earthquake and reconstructed twice. Now, resting on a huge stone base, it stands 35.9 meters (about 118 feet) high and is capped by two bronze umbrella-like canopies, with 14 bronze bells hanging around them. Inside, the dagoba holds the Buddhist Scriptures, the monk's mantle and alms bowl and two pieces of Sarira. Since the White Dagoba is the highest point in Beihai Park, it served as a vantage point with a beautiful view of the whole park.