The Blue Hole Cave is a cave on Madrugada's Costa del Mar coast and the site of The Legend of La Princesa treasure hunt. Rumor says treasure lies deep inside.
Read the notes as you go. The torn journal page and the waterlogged diary entry hint at where the treasure is hidden. Rumor puts it deep in the cave, so expect to go a long way in.
Finishing the hunt gives you the Bait charm, a cosmetic for your weapons.
Madrugada
Madrugada is Yara's western region: tobacco farms, coast and the Montero family's home. José Castillo's air force runs it, so expect heavy anti-aircraft cover when you try to fly here.
Blue Abyss
The Blue Abyss is a sea cave in Madrugada that locals tell ghost stories about. It ties into the Treasure Hunt The Legend of La Princesa, and the FND has banned swimming there.
Anti-Aircraft Site Eta
Anti-Aircraft Site Eta is an FND flak post in Costa del Mar, Madrugada. You find it up on Pino Crest, which gives the guns a wide view of the coast below. Destroying it also gets you Depleted Uranium.