Svartifoss, Iceland.

Svartifoss (Black Fall) waterfall with its basalt columns in 
Skaftafell, Vatnajökull National Park, Iceland. The basalt hexagonal shaped columns were formed inside a lava flow which cooled extremely slowly which resulted in the crystallization of the rock.

Svartifoss (Black Fall) is a waterfall in Vatnajökull National Park in Iceland and is one of the park’s most popular sights.

Svartifoss is surrounded by dark lava columns, which gave rise to its name. Other well-known columnar jointing formations are seen at the Giant’s Causeway in Northern Ireland, Devil’s Tower in Wyoming, USA and on the island of Staffa in Scotland.

The base of this waterfall is noteworthy for its sharp rocks. New hexagonal column sections break off faster than the falling water wears down the edges. These basalt columns have provided inspiration for Icelandic architects, most visibly in the Hallgrímskirkja church in Reykjavík, and also the National Theatre. [Source]

Vatnajökull National Park is one of three national parks in Iceland. It encompasses all of Vatnajökull glacier (the largest in Europe) and extensive surrounding areas. These include the national parks previously existing at Skaftafell in the southwest and Jökulsárgljúfur in the north.

If you’re wondering why the falling water appears that way, it’s because the image is a long exposure photograph where the shutter was left open for 10 seconds.