Begin the day with hotel pickup from downtown Puerto Princesa or the airport and head to Sabang Wharf, arriving around 8:00 AM. Board a pump boat and cruise into the mouth of the cave, home to monitor lizards, monkeys, snakes, and other wildlife, some of which is exclusive to Palawan. Following a short walk, ride a paddle boat to the Underground River and marvel at this unique natural wonder. Grab an audioguide and sail through the narrow waters, past stone walls with hundreds of years of history. Keep an out for interesting shapes and colors in the caves and on the walls. Upon return to the wharf, lunch will be served. Savor a feast of local cuisine and then set off on the optional excursions, either a zip-lining adventure or a peaceful mangrove paddle boat tour. Return to your hotel for some downtime before heading back out for the evening portion of the tour. Drive to an offsite restaurant for your dinner before heading on to a river located some 30 kilometers from the city center. Aside from the fireflies and the stars, you'll also see the water light up by the bioluminescent plankton. Following the tour of the estuary, return to the wharf and then to your hotel.