When you google Basalt Columns, the images will blow you away! This beauty and a hidden gem - Stuðlagil, the Basalt Column Canyon in Jökuldalur valley, Eastern Iceland.

Basalt Columns, Iceland Image source via ourwanders.com
The Basalt Column canyon towers over a turquoise glacial river, making for one of the most stunning and photographic sights in the country. Until in recent years, these glacials were hidden, as it was completely submerged under the water. The water level of the river (called the Jökla river) fell and behold, revealing the canyon.
For centuries, the river Jökla (approximately 150 kilometres) was one of the largest and most powerful glacial rivers in Iceland that divide Jökuldalur Valley into two parts. The farmers and villagers on either side were completely cut off from each other. As it was a forceful river, a hydroelectric plant, Kárahnjúkavirkjun was built and created a reservoir. This causes the water level to fall. This, of course, was controversial because of the negative impact on the environment, but then again, it revealed these beautiful and amazing Basalt columns.
These hexagonal columns are formed in a process called columnar jointing, according to geologists. When the basaltic lava flows and cools slowly over time, it shrinks in volume and cracks into symmetrical patterns. These hexagon shapes clustered together to form slender columns.

Image source via hiticeland.com
Previously, the water was murky brown due to the glacial sediment. But now the river is fed by the crystal-clear waters of Hálslón Reservoir. As a result, the waters that flow through Stuðlagil Canyon are a vibrant turquoise.
You should also see the Stuðlafoss Waterfall, also known as the Basalt Column Waterfall, flows into a branch of the Jökla. The cascade pours down from moss-covered basalt columns. It is indeed a spectacular sight!
How to get there?
The best time to travel there is between July and April.
There are two options for how one can get to the canyon. From the farm Grund, you can walk about 250 meters walk to the viewpoint where you can look down on the majestic columns and the clear blue colour of the river. You can also descend a narrow path to the bottom of the river. But beware of the slippery-ness of the pathway.
Alternatively, if you are in for a hike, you can also park your car on the parking lot at the farm Klaustursel. The hike will bring you closer to the canyon. Since the hike, both ways is 8 kilometres and stops by the waterfall, and the hike will probably be two to three hours. For photography, it is recommended to be in the canyon in the morning.