A rare “ring of fire” eclipse of the sun cuts across the Americas on Saturday, stretching from Oregon to Brazil, and huge crowds were on the move before dawn in cities, rural areas and national parks to try to catch a glimpse of it.

For the small towns and cities along its narrow path, there was a mix of excitement, worries about the weather and concerns they’d be overwhelmed by visitors flocking to see the celestial event, also called an annular solar eclipse. Clouds and fog threatened to obscure the view of the eclipse in some western states, including California and Oregon.

Unlike a total solar eclipse, the moon doesn’t completely cover the sun during a ring of fire eclipse. When the moon lines up between Earth and the sun, it leaves a bright, blazing border.