Leaving Ha Giang, the road climbs over the Quan Ba Pass (Heaven’s Gate) around 40km from the city. Poetic licence is a national pastime in Vietnam, but this time the romantics have it right. The road winds over a saddle and opens up on to an awesome vista of knobbly topped limestone mountains.
At the top of Quan Ba Pass is an information centre and lookout with amazing views down into Tam Son. An English-language information board details the 2011 initiative to declare the Dong Van Karst Plateau part of the Unesco Global Network of National Geoparks. It’s the first Unesco-recognised geopark in Vietnam and the second one in Southeast Asia, after Langkawi Geological Park in Malaysia.