Picture Post is an interesting (and NASA-funded) citizen science project that turns photographers into citizen scientists, crowdsourcing the task of environmental monitoring. Anyone around the world can install a Picture Post:
A Picture Post is a 4”x4” post made of wood or recycled plastic with enough of the post buried in the ground so it extends below the frost line and stays secure throughout the year. Atop the post is a small octagonal-shaped platform or cap on which you can rest your camera to take a series of nine photographs.
People who walk by can then use the guide on the post to capture 9 photos in all directions, and upload them to the Picture Post website. The resulting panoramas can then be browsed by date, giving a cool look at how a particular location changes over time.