Pematang Gadung is one of the better patches of intact forest left on Bangka, an island whose interior has been significantly altered by tin and kaolin mining over the centuries. The nature reserve offers walking trails through lowland tropical forest — hornbills are among the birds you might see, along with various sunbirds, kingfishers, and if you're patient, some of the smaller forest mammals.
It's about an hour's drive south of Pangkalpinang, which keeps visitor numbers low. Bring decent footwear, water, and mosquito repellent. There are no guides on-site as a matter of course, so asking at your hotel in advance for a contact is worthwhile if you want to go beyond the main trails. The combination of intact canopy and relative quiet makes this the most rewarding stop for anyone interested in Bangka beyond its beaches.