Oro Fortress Island

Oro was fortified from 1915 as a coastal artillery position guarding the approaches to the Gulf of Finland, and it stayed in military hands for a century, closed to everyone else, until it was opened to visitors in 2015. What remains is the whole apparatus: gun positions including heavy pieces left in place, ammunition tunnels, barracks, a narrow-gauge railway that moved shells around the island, and the roads and buildings of a garrison. Because it was undisturbed for so long, the flora is exceptional, with a long list of plants, butterflies and moths recorded on a small island. Trails run through pine forest and along the shore, and there is a guest harbour and simple accommodation.

The main sights

• Heavy coastal guns in place - the artillery left on their mountings.
• Ammunition tunnels and a shell railway - the logistics of the battery.
• Exceptional island flora - the result of a century of restricted access.
• Garrison buildings and roads - the infrastructure of a closed island.

When to go

June to August, when boats run; the island is effectively closed the rest of the year. A day, better overnight. Book both boat and accommodation ahead.

Things to know

Boats run only in summer and are weather dependent. Accommodation is limited and simple. Some structures are unsafe and fenced. Facilities and supplies are minimal, so bring what you need.

Nearby

Kasnas is north; Bengtskar lies east.