Cactus Knows No Borders

The Milky Way arc above the Organ Pipe Cactus National Monument and UNESCO biosphere reserve in extreme southern Arizona sharing a border with the Mexican state of Sonora. This is the only place in the US where the Organ Pipe Cactus grows wild. The green “clouds” are airglow, natural emission of the Earth upper atmosphere. The yellow-orange glow is the light from nearby towns.