Part of Parque Nacional Sierra de Bahoruco, the ‘hole’ at Pelempito is actually a deep gorge formed when the Península de Pedernales rammed into Hispaniola umpteen million years ago. The tourist office, perched at the edge of a cliff at 1450m, offers breathtaking views, north and east, of completely untouched national park. It has information (in Spanish) on the area's flora and fauna, and a number of short nature walks have small signs identifying the various plants.
Serious birdwatchers scoff that this is a poor birdwatching location, but for the casual tourist the views make it worth the drive.
Pelempito sits on the southern side of the Sierra de Bahoruco. The turnoff is about 12km east of Pedernales. Shortly after the turnoff to Bahía de Las Águilas, you’ll cross a small bridge. Immediately afterwards, turn left onto a dirt road that swings around to the paved road north to Hoyo de Pelempito (it ends up being the same road that leads to Bahía de Las Águilas, but you’ll go in the opposite direction). Around 13.5km later, you’ll come to a ranger station. From here, the paved, highway-like road continues for 16km, and then turns into a rutted dirt track for the last 7km. Rains frequently destroy this part of the road, so you’ll need a 4WD with some clearance.