In 1962 Vietnam’s first national park was established around a narrow valley between forested limestone hills on the borders of Ninh Binh, Thanh Hoa and Hoa Binh provinces, containing over two hundred square kilometres of tropical evergreen rainforest. Cuc Phuong is well set up for tourism and sees a steady stream of visitors, attracted principally by the excellent primate rescue centre, but also by the easy access to impressively ancient trees. With more time, you can walk into the park interior, overnight in a Muong village and experience the multi-layered forest. The most enjoyable time for walking in these hills is October to January, when mosquitoes and leeches take a break and temperatures are relatively cool – but this is also peak season. Flowers are at their best February and March, while April and May are the months when lepidopterists can enjoy the “butterfly festival” as thousands of butterflies colour the forest.