10 Breathtaking Basalt Columns Around the World

Basalt columns are natural pillars made of hardened lava, caused by the contraction of volcanic rock as it cools. The columns are often shaped like hexagons, pentagons, or octagons due to the "rapid"—i.e., over the course of a century—cooling process, and they can often form as vertical cliffs or terraced steps, sometimes descending directly into the ocean.

What Is a Basalt Column?

Basalt columns are created by the cooling and contracting of lava—made of 90% basalt—which causes the ground to crack into long, geometric columns. This process is called columnar jointing.

In a 2018 study, researchers at the University of Liverpool replicated the formation of these rocks and found that fracturing occurs at 194 to 284 degrees Fahrenheit below the point at which magma crystallizes into rock (1796 degrees). That means some of the world's most famous basalt columns, like those at Giant's Causeway in Northern Ireland and Devils Postpile in California, formed at temperatures between 1544 and 1634 degrees.

From Mexico to Namibia, here are 10 places to admire these fascinating geologic wonders.

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Giant's Causeway

Hexagonal basalt columns descending into sea on Northern Ireland coast — Chiara Salvadori / Getty Images

Giant's Causeway is perhaps the world's most extraordinary and well-known example of basalt columns. Some 50 to 60 million years ago, a volcanic plateau of molten basalt formed on the north coast of Northern Ireland, and as it cooled, the hardening lava cracked into tidy hexagonal, columnar tiles that now border and descend into the sea.

Now a UNESCO World Heritage site and national nature preserve (serving as a safe haven for marine life and seabirds), Giant's Causeway is visited by about a million people per year. Its name hails from ancient folklore: Before humans knew much about geology, it was believed that the geometric cracks were formed by the footsteps of giants.

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Basaltic Prisms of Santa María Regla

Water rushing down tall and columnar basalt joints, forming rainbow — CassielMx / Getty Images

The water rushing over the Basaltic Prisms of Santa María Regla make the ancient pillars look especially surreal. The columns are polygonal and vary in height from 100 to more than 150 feet tall. They contain a ravine whose water flows from the San Antonio Dam, often times causing a rainbow to form at the base of two waterfalls. The tourist attraction is located in Hildago, Mexico, and can be enjoyed via walkways and hanging bridges.

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Devils Postpile National Monument

Low-angle view of tree-topped, columnar basalt cliff formation — LucynaKoch / Getty Images

One of the most fantastic displays of basalt columns in the U.S. is that near Mammoth Mountain in California. Apart from Devils Postpile's regal appearance—a vertical, tree-topped cliff composed of long and symmetrical, interlocking pillars thought to be between 400 and 600 feet in thickness—the formation has had a whirlwind history. It was once included in Yosemite National Park, then removed due to the discovery of gold in the area, then almost demolished for the purpose of a hydroelectric dam, saved by the legendary John Muir, then—finally—protected as its own national monument. The formation of Devils Postpile is believed to be relatively recent, within the past 100,000 years.

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Fingal's Cave

Scotland's Fingal's Cave and Northern Ireland's Giant's Causeway were caused by the same Paleocene-era volcanic event. However, the former offers a unique viewing experience. Here, on the uninhabited island of Staffa, the basalt columns line the walls of a sea cave like blocky stalactites made of hardened lava.

The cave is 72 feet tall, 270 feet deep, and known particularly for its natural acoustics, which once inspired 19th century composer Felix Mendelssohn to write an overture in its name. Visitors can experience the bizarre echoing and explore the otherworldly scene by walking on footpaths along the columns.

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Svartifoss

Large waterfall flanked by columnar jointed volcanic rock — FEBRUARY / Getty Images

Another basalt-column cliff decorated by falling water, Svartifoss in southern Iceland's Vatnajökull National Park is called "black waterfall" in Icelandic due to the dark color of the volcanic rock. The basalt formation, surrounded by Iceland's signature lush greenery, has inspired such architectural works as the National Theatre in Reykjavik and was featured in Bon Iver's music video for the song "Holocene." It can be reached via a short hiking track, but visitors are warned against swimming as some of the basalt has cracked off from the cliff and created quite a sharp surface under the water.

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Takachiho Gorge

Boat paddling through volcanic river in shadow of basalt columns — Ippei Naoi / Getty Images

The basalt columns at Takachiho Gorge were formed some 270,000 years ago as a result of four eruptions of the Mount Aso volcano. Since, the Gokase River has cut through the columns, creating a narrow, V-shaped chasm through which beautiful blue-green water flows. Boats float down the four-mile gorge in the shadow of these 300-foot, red-tinted cliffs. The site has been protected as a National Scenic Spot and Natural Monument in Japan since 1934.

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Cape Stolbchatiy

Basalt columns partly submerged in the sea — HomoCosmicos / Getty Images

Quite similar to Giant's Causeway are the cliffs at Cape Stolbckatiy on Kunashir Island, between Russia and Japan. The rocks crack in the same hexagonal shape as the UK country's star attraction, and they create precipitous, 150-foot-tall seaside cliffs three times the height of Giant's Causeway. In places, the gray basalt columns descend diagonally like steps into the ocean and crop up offshore as rocky islands. The formations were created by an eruption of the nearby Mendeleev Volcano and are named after the Russian word for “columnar."

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Organ Pipes

Named for the way they resemble the actual pipes of an organ, these Namibian rocks—some of them more than 15 feet tall—are about 150 million years old. They are located near another volcanic feature, Burnt Mountain, whose solidified lava flow is a popular subject for photographers. Both the formations have an extraordinary red tint that makes them appear fiery when the sun hits them right.

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Cape Raoul

Basalt columns covered in vegetation forming seaside cliffs in Tasmania — Posnov / Getty Images

Originally dubbed Basaltic Cape by its founders, the towering columns and shrubby cliffs on the southeast coast of Tasmania, Australia, were renamed Raoul by French explorers in the early 19th century. The formations were caused by a Jurassic-era volcanic event (about 185 million years ago) that is believed to have covered a third of the island. Erosion from the wind and sea has created a sort of noncohesive, craggy aesthetic.

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Hexagon Pool

Waterfall cutting through hexagon basalt rock formation into pool — Avi_Cohen_Nehemia / Getty Images

Swimming in a pool surrounded by steep, 15-foot basalt cliffs is a once-in-a-lifetime experience to be had in Israel's Yehudiya Forest Nature Reserve. Most of the columns that contain the 65-by-100-foot Hexagon Pool—a scenic swimming hole formed by the Meshushim Stream rushing grandly over the formations—are greater than a foot in diameter. This is the most spectacular of many basalt formations within the reserve, all caused by activity in the Golan Heights volcanic field.