Mack Arch Rock at sunrise, Oregon, USA

A rocky wildlife refuge. Mack Arch Rock

Colossal sea stacks jutting out from the Pacific are a common sight along this stretch of the USA’s west coast. These rock formations run next to a grassy headland overlooking a mostly inaccessible section of coastline in the US state of Oregon. That bridge-like one at the back is known as the Mack Arch, one of the largest naturally formed arches on the Pacific Coast and part of the Mack Reef archipelago.

These clusters of sea stacks and beaches are home to seabirds like cormorants, black oystercatchers, gulls and murres, as well as harbour seals and other marine wildlife. To help preserve this sanctuary, the US government has made it part of the Oregon Islands National Wildlife Refuge and closed the area off to the public. So, if you're looking to get a close-up view of Mack Arch, you'll have to do so by plane or boat.