April 22nd is Earth Day, and Vimeo is celebrating the environmental holiday with an appropriate documentary. On the video site's On Demand platform, viewers can purchase Planetary, a film that explores the connections between people all over the planet.

Planetary began as a short film called "Overview," which became a hit on Vimeo after its release in 2013. Encouraged by the short's success, filmmaker Guy Reid turned to Kickstarter, where he raised more than $86,000 to fund a feature film. That film is Planetary, which can now be rented for $5.99 on Vimeo On Demand.

The harder question to answer, though, is what Planetary is actually about. A press release from Vimeo calls the film "a cross-continental cinematic journey and film-going experience like no other. In a stunning visual exploration, the film interweaves imagery from Nasa Apollo missions with visions of the Milky Way, Buddhist monasteries in the Himalayas, and the cacophonous sounds of downtown Tokyo and Manhattan,...