On December 6th, 1884 – 128 years ago today – the capstone was set on the Washington Monument, signifying the completion of the world’s tallest stone structure and the world’s tallest obelisk. The marble, granite, and bluestone gneiss structure is a distinguishable and must-photograph landmark of Washington, D.C. To see more shots of the monument on Instagram, tap the location text above this image. Photo by @jonkratz