Biak-na-Bato National Park

Biak-na-Bato - "split rock" - protects the gorge of the Balaong river where it cuts through Bulacan's limestone, and the result is a compact park with a lot packed into it: turquoise pools under cliff walls, hanging footbridges swinging over the water, and a network of dozens of caves in the surrounding karst, of which a handful are opened to visitors with guides. Bahay Paniki, the largest, is entered by wading and swimming a stretch of underground river beneath a roof full of bats; other caverns are dry scrambles through chambers and squeezes. Above ground, trails run along the gorge between swimming spots that fill with families at weekends and stay quiet midweek. The park also carries national historical weight as a mountain refuge during the revolution against Spain, marked by monuments near the entrance, but the day-to-day experience is straightforwardly outdoors: bridges, caves, river pools and forest an hour and a half from the capital.

What you actually see

• The gorge pools - turquoise water under limestone walls.
• Bahay Paniki cave - the underground river swim among bats.
• The hanging bridges - footbridges over the Balaong.
• The karst trails - forest paths between cave mouths.

When to go

November to May; the river rises fast in the rainy months and caves close. Weekdays for quiet, weekends for the full family-picnic scene.

Honest expectations

Cave routes involve wading, swimming and squeezes - not for the claustrophobic, and guides are mandatory. Rocks are slick. Facilities are modest and litter builds after busy weekends.

Nearby

San Miguel's old town, the Sierra Madre foothills and the road on toward Nueva Ecija fill the surrounding day.