Perched atop a large volcanic rock offshore from Villa, this eerie fort was constructed to defend the town of Calliaqua and affords fantastic 360-degree views of the southern shoreline. There are 225 steps in the spiral staircase that has been carved into the rock; take care as it can be slippery, with small stones often covering the walkway – bring footwear. At the top, 200ft above sea level, you'll find two batteries of cannon and a picnic area.
Fort Duvernette is only accessible by boat. Ask for Nato in Indian Bay, who will take you over in his little rowboat for EC$27 per visitor. Alternatively, motorboat operators hang out at the Young Island dock and charge around EC$100 round trip.
Technically there's an admission fee to the fort, but there's not always an official there to collect it.