Hanoi makes a convenient base for day trips into the surrounding countryside. Halong Bay is the most popular, though it's a long day given the 3 to 4 hour drive each way. Ninh Binh's Tam Coc and Trang An are closer and easier to fit into a single day, while Perfume Pagoda draws pilgrims for its religious significance. Ba Vi National Park suits hikers, and Mai Chau, a Thai ethnic minority valley about 3 hours away, is better done as an overnight than a rushed day trip.