One of the most well-known projects in which crochet is used to spread the word about a cause is the Hyperbolic Crochet Coral Reef Project. The project was launched back in 2005. As you may know, a coral reef was crocheted by multiple people to raise awareness of the ecological issues affecting these reefs around the world. The project has since had multiple spinoff projects that continue to raise this awareness.
One of these spinoff projects is currently on display at the Smithsonian National Museum of Natural History. It has been there since October and will be on display there through April 24th so if you are in that are you might want to take the time to get out there and check it out up close.
Here’s one lovely description of the project:
“Atolls and clusters of crocheted corals, made of both yarn and found materials, weave their way into unique coral communities. By using particular crocheting techniques that employ hyperbolic geometry, these reefs take shape into complex, natural-looking forms.”
Incidentally another hyperbolic crochet coral reef was just on display in the UK.