Ha Long Bay, Bay in Quảng Ninh Province, Vietnam

Ha Long Bay is a sea inlet in Quang Ninh Province in northern Vietnam, where steep limestone pinnacles rise directly from the green water. The surface of the rocks is covered with tropical vegetation, while the base is often carved through with caves and small grottoes.

Archaeological surveys found traces of prehistoric people in the bay area, including the Soi Nhụ culture (about 18,000–7,000 BC), the Cái Bèo culture (7,000–5,000 BC) and the Hạ Long culture (about 5,000–3,500 years ago). Nguyễn Trãi praised the bay in his poem Lộ nhập Vân Đồn around 500 years ago as a "rock wonder in the sky". The core zone was listed as a UNESCO World Heritage Site in 1994 and again in 2000.

Fishers have lived for centuries in floating villages between the cliffs, using bamboo and wooden boats for their daily work. Travelers can watch children playing in the houses on the water and adults mending their nets at the doorstep.

Most visitors travel by boat between the islands, with longer tours often including a night on board. Trips usually depart early in the morning and return in the late afternoon, depending on the route chosen.

Hang Đầu Gỗ, the largest grotto in the bay, was visited by French tourists in the late 19th century, who named it Grotte des Merveilles. Its three chambers hold numerous stalactites and stalagmites, along with 19th-century French graffiti.