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Manjang Cave

Manjang Cave (만장굴; map; Manjanggul), located in Jeju’s northeast, is one of the island’s most extraordinary natural landmarks. As part of the UNESCO-recognized Geomun Oreum Lava Tube System, this lava tube stretches approximately 7.4 kilometers. With its towering 25-meter ceilings and expansive 18-meter widths, it is among the longest and largest lava tubes in the world. While the entire cave system remains off-limits to preserve its delicate ecosystem, visitors can explore a 1-kilometer section, offering a glimpse into Jeju’s volcanic origins.

Geology

Manjang Cave, a product of the Geomun Oreum Volcano’s ancient eruptions, is a prime example of how molten lava shapes the Earth. Formed over 100,000 years ago, the cave represents a dynamic period in Jeju’s geological history when hot lava carved underground channels before cooling and solidifying into its present form.

Inside the cave, visitors encounter some of the most pristine volcanic formations globally, which have remained largely undisturbed over millennia. Lava stalactites hang from the ceiling, formed as molten rock dripped and cooled. On the ground, stalagmites rise where dripping lava once pooled.

One of the most striking features is the lava flow lines etched into the walls. These lines mark the height of lava as it surged through the cave, offering a tangible timeline of its movement. Lava benches, formed as molten rock cooled in layers, reveal how the cave expanded during repeated lava flows.

Manjang Cave’s highlight is the world’s largest lava column, a towering 7.6-meter structure at the end of the tourist path. This feature formed when descending lava met rising flows, creating a natural pillar that illustrates the immense power and scale of volcanic activity.

Inside the Cave

Manjang Cave offers a journey into Jeju’s underground world, beginning at its second entrance. Visitors descend steep stairs into a dark interior where temperatures remain a constant 11-21°C, providing a refreshing contrast to the island’s warm, humid climate.

The dim lighting inside enhances the cave’s mysterious ambiance while preserving its fragile ecosystem. The path is a mix of natural rock and wooden walkways, guiding visitors through 1 kilometer of the volcanic cavern. Sturdy footwear is recommended. Uneven terrain and occasional water puddles can make the journey slippery.

Highlights within the cave include:

  • Lava Flow Lines: These horizontal markings along the walls show the height of lava flows as they coursed through the cave, offering a snapshot of volcanic activity frozen in time.
  • Turtle Rock: A famous formation that resembles a turtle, believed to represent Jeju Island itself. It serves as a favorite photo spot for visitors.
  • Lava Toes: Smooth, rounded formations on the cave floor, created as flowing lava cooled and solidified. Their shape resembles toes, adding to the cave’s organic charm.

Ecology and Preservation

Manjang Cave’s cool, dark interior provides a habitat for rare and specialized species. Among these are bats, including the common bent-wing bat, which form large colonies within the cave, and the Jeju cave-spider, a species found only in Korea.

This fragile ecosystem has made Manjang Cave a focus of conservation efforts. The cave’s delicate balance of life and geology necessitates strict visitor guidelines, such as limiting access to a 1-kilometer section to minimize human impact. To further protect its integrity, artificial lighting is kept minimal, preventing algae growth that could harm the natural formations.

In recognition of its unparalleled ecological and geological value, Manjang Cave was designated as a Natural Monument (No. 98) in 1962. It was later included in the UNESCO World Heritage Site listing as part of the Geomun Oreum Lava Tube System in 2007.

Visitor Information

  • Admission: Adults ₩4,000; Youth and Children ₩2,000.
  • Hours: Open daily from 9:00 AM to 6:00 PM (last entry at 5:10 PM).
  • Accessibility: The uneven terrain may challenge visitors with mobility issues. The route includes stairs and natural paths, so sturdy shoes are necessary.
  • Facilities: A parking area, restrooms, and a visitor center with interpretive displays are available near the entrance.
  • Best Time to Visit: Manjang Cave offers a cool retreat year-round. Mornings are less crowded, providing a quieter experience.

Cultural and Scientific Importance

Manjang Cave was discovered in 1946 by a local schoolteacher and his students. Since then, it has been a focus of international research, particularly on volcanic processes and subterranean ecosystems. Its relatively undisturbed state allows researchers to study lava tube formation, rare cave-dwelling species, and ancient volcanic activity.

The cave’s significance extends to its role in storytelling and local culture. The Turtle Rock, for example, has become a symbol of Jeju Island, inspiring both visitors and locals with its natural artistry.