One of the wonders of Vietnam is Ha Long Bay, a UNESCO World Heritage Site located in the Gulf of Tonkin. It is known for its emerald waters and thousands of towering limestone islands and islets. The bay is home to diverse marine life, including coral reefs, fish, and rare species like the Cat Ba langur. Visitors can explore the bay by taking a cruise or kayaking through the stunning limestone formations. The area is also rich in cultural heritage, with floating fishing villages and caves that showcase ancient Vietnamese history. Ha Long Bay is a breathtaking natural wonder that offers a unique and unforgettable experience for travelers.