Halong Bay is a spectacular blend of sea and islands with 1,969 islets which are mostly lime-stone. Long-standing islands of Halong Bay with various sizes and shapes are relics of various geological operations including orogeny, marine transgression and marine regression in 5.000 years ago.
Almost half of Cat Ba Island (with a total area of 354 sq km) and 90 sq km of the adjacent waters were declared a national park in 1986 to protect the island’s diverse ecosystems. Most of the coastline consists of rocky cliffs, but there are some sandy beaches and tiny fishing villages hidden away in small coves.
Quan Lan Island belongs to Bái Tu Long Bay; part of an island range on the outside of the gulf of Bac Bo. It has an area of 11 sq. km, and features eight populated hamlets. Quan Lan Island stretch toward East – West from the foot of Vân Ðon Range to the Gót Mount with many high mountains to the east barring waves and winds, protect the villages. The island is situated on an important navigation route that connects China, Japan, Thailand and Philippines to Vietnam. Along two sides of the island are tens kilometres of sand beaches. This is the endless resource for glass making which the sea gives to man and it is also the extremely interesting tourism.
In the Ngoc Vung – Quan Lan islands itinerary, one will visit Cong Tay Island, which lies at the Bái Tu Long Bay, 40 km away from the Bai Cháy Tourist Wharf. From Cam Pha, express boats will take you 30 minutes or 90 minutes by common boats to reach Cong Tây Island. Cong Tây Island is considered the Cinderella in a legendary tale. The Cam Pha Coal Construction and Port Company built a resort in the island to attract holidaymakers. A system of villas and restaurants lies very close to the beach. Red brick-paved, coconut-lined roads lead from the villas to the beach. Hammocks are available here and there for tourists to relax and view the sea.
Geologically, Lan Ha is an extension of Halong Bay but sits in a different province of Vietnam. Around 200 species of fish, 500 species of mollusc, 400 species of arthropod, and numerous hard and soft coral live in the waters here, while larger marine animals in the area include seals and three species of dolphin.