Sierra Bermeja in southwestern Puerto Rico

This unassuming view of Sierra Bermeja (i.e., vermilion range in Spanish) hides some interesting science. The mountain range contains the oldest rocks in the island, which have been dated at approximately 190 million years of age. The rocks are a mix of all 3 main types: igneous, sedimentary and metamorphic. The range is located next to the Caribbean Sea, along Puerto Rico's south coast, and rises up to a modest 900 feet (300 meters) in elevation.

Smartphone camera on Motorola G-Pure.

GNU Image Manipulation Program (GIMP) on GNU/Linux. (1) Counter-clockwise rotation by 0.5 degrees. (2) Minimal cropping to 4,128 x 2,752 from the original at 4,160 x 3,120.