The bay famous for its unique rock formations known as karsts is Ha Long Bay in Vietnam. This UNESCO World Heritage Site features an extraordinary landscape of thousands of limestone islands and pillars, eroded by rain and sea over millions of years. The area's stunning karst topography, comprised of towering cliffs and hidden caves, attracts tourists for its natural beauty and recreational activities, such as kayaking and boat tours. The cultural significance of Ha Long Bay and its breathtaking views make it a popular destination for visitors.