They Built It Inside a Cave (10 Photos)

Somebody looked at a cave and started building

Most caves get a handrail and a ticket booth. These ten got a royal pavilion, a church with 20,000 seats, a railway and a chandelier from a Brooklyn theater. All of them are real, and all of them can still be visited.

More: None of These Rooms Has a Window (10 Photos)

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🛕 Kuha Karuhas Pavilion — Phraya Nakhon Cave, Prachuap Khiri Khan, Thailand 🇹🇭

A gold-and-red royal pavilion stands on a mound of earth in Phraya Nakhon Cave, with trees growing around it. A hole in the roof lets sunlight reach the floor. The pavilion was built to mark King Chulalongkorn’s visit in 1890: it was constructed in Bangkok and then reassembled inside the cave.

💡 Hike Fact: The last stretch is on foot: a climb of about 430 meters up the hill from Laem Sala Beach. The pavilion has become a symbol of Prachuap Khiri Khan province.

📷 Photo and cover crop: “Phraya Nakhon Cave” by Niels Mickers / Wikimedia Commons (CC BY 3.0 NL)

📂Artwork File · Seen Apr 2026 — Built in Bangkok, this royal pavilion was assembled inside a sunlit cave. The full story, with every source

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⛪ Santa Cueva — Covadonga, Asturias, Spain 🇪🇸

A small chapel sits in the mouth of a cave partway up a cliff, and a waterfall pours out of the rock right below it. The Santa Cueva de Covadonga is a natural cave that holds the statue of the Virgin of Covadonga, known as La Santina, the patron of Asturias.

💡 History Fact: The chapel is newer than it looks: the current one was built in the early 1940s. The cave also holds the tomb of Pelayo, the leader tied to the Battle of Covadonga in 722.

📷 Photo and cover crop: “CUEVA SANTA EN COVADONGA” by Manuel Velazquez / Wikimedia Commons (CC BY 3.0)

📂Artwork File · Seen Jul 2024 — A wooden church once hung from this cliff cave until fire took it in 1777. The full story, with every source

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⛪ Cave Church of St. Simon the Tanner — Mokattam, Cairo, Egypt 🇪🇬

Curved rows of seats climb toward the daylight under a ceiling of bare stone. This is a church: the Monastery of St. Simon the Tanner in the Mokattam hills can hold up to 20,000 people. Cairo’s Coptic garbage collectors built it, using a cave that was already there and the slope leading into it.

💡 Community Fact: It started small. By 1975 the community had built its first church out of tin and reeds. The cave church is now described as one of the largest churches in the Middle East.

📷 Photo: “Samaan monastery” by Ehab ahmed mohammed / Wikimedia Commons (CC BY-SA 4.0)

📂Artwork File · Standing Apr 2026 — Cairo’s garbage collectors built a church inside a Mokattam cave. The full story, with every source

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🎻 Volcano Room — Cumberland Caverns, McMinnville, Tennessee, USA 🇺🇸

A crystal chandelier hangs from bare rock above tables set out on the cave floor. The Volcano Room at Cumberland Caverns is a concert and event room 333 feet below the ground.

💡 Chandelier Fact: The 1,500-pound chandelier came from the Loew’s Metropolitan Theatre in Brooklyn, New York. The TV concert series Bluegrass Underground was taped at Cumberland Caverns from 2008 before it moved to another Tennessee cave.

📷 Photo: “Volcano Room of Cumberland Caverns” by RL0919 / Wikimedia Commons (CC BY-SA 4.0), resized

📂Artwork File · Seen Jul 2021 — A Brooklyn theater’s 1,500-pound chandelier hangs 333 feet underground. The full story, with every source

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🎭 St. Michael’s Cave Auditorium — Upper Rock, Gibraltar 🇬🇮

Rows of theater seats and a lit stairway fill a chamber hung with stalactites. St. Michael’s Cave is a natural limestone cave inside the Rock of Gibraltar.

💡 Cave Fact: During World War II the cave was prepared as an emergency hospital, but was never used as one. It has been a theater since the early 1960s.

📷 Photo: “Gibraltar Auditorium 01” by Ronny Siegel / Wikimedia Commons (CC BY 4.0)

📂Artwork File · Standing May 2026 — Readied as a WWII hospital, this Gibraltar cave has hosted theater since the early 1960s. The full story, with every source

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☀️ Tham Khao Luang — Phetchaburi, Thailand 🇹🇭

A shaft of sunlight drops through the roof onto a tiled floor, golden Buddha images and a row of stupas. Tham Khao Luang is a cave used as a temple, and the light comes from openings in the ceiling.

💡 Royal Fact: One Buddha image here was cast by order of King Chulalongkorn (Rama V) in honor of two earlier kings, Nangklao (Rama III) and Mongkut (Rama IV).

📷 Photo: “Tham Khao Luang Cave 2014-04 –2” by Zinneke / Wikimedia Commons (CC BY-SA 3.0)

📂Artwork File · Standing May 2024 — Rama IV paid villagers to guard this cave’s gilded Buddhas from gold thieves. The full story, with every source

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🏚️ Tuberculosis Huts — Mammoth Cave, Kentucky, USA 🇺🇸

A flat-roofed stone hut stands in the dark of a cave passage. In 1842 Dr. John Croghan, who owned Mammoth Cave, invited 16 tuberculosis patients to live underground, hoping the cave air would cure them. Two stone huts are the last that remain.

💡 Medical Fact: It did not work. Five patients died inside the cave, the experiment ended in early 1843, and Croghan himself died of tuberculosis in 1849.

📷 Photo: “1840s underground tuberculosis hospital hut (Mammoth Cave, Kentucky, USA) 1” by James St. John / Wikimedia Commons (CC BY 2.0)

📂Artwork File · Standing Mar 2025 — Five tuberculosis patients died in this 1840s hospital inside Mammoth Cave. The full story, with every source

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🚂 Cave Railway — Postojna Cave, Slovenia 🇸🇮

Open yellow carriages wait at a platform deep underground. At Postojna Cave the tour includes a train ride, and has for a long time: the world’s first railway in an underground cave opened here in 1872.

💡 Railway Fact: The first carriages had no engine. Cave guides pulled them along the track by hand. In 1899 the cave also got the world’s first underground post office.

📷 Photo: “Postojna Cave train” by Simon Legner / Wikimedia Commons (CC BY-SA 4.0)

📂Artwork File · Seen Sep 2025 — Cave guides moved the first visitor cars here by hand in 1872. The full story, with every source

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🛕 Temple Cave — Batu Caves, Selangor, Malaysia 🇲🇾

Visitors cross a paved floor toward a painted shrine tower, with daylight coming in through the far end of the cave. The main shrine at Batu Caves is at the top of 272 steps, set deep in a cave around 100 meters high.

💡 Temple Fact: A Hindu temple dedicated to Lord Murugan was completed here in 1891. The concrete steps came later, in 1940.

📷 Photo: “Thaipusam 2025 Interior View of Temple Cave Main Chamber and Shrines at Batu Caves (250212)” by *angys* / Wikimedia Commons (CC BY-SA 4.0)

📂Artwork File · Seen Jul 2025 — Pilgrims climb 272 concrete steps, built in 1940, to reach this cave temple. The full story, with every source

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⛪ Cave Church — Gellért Hill, Budapest, Hungary 🇭🇺

An arched iron gate fills an opening in the side of the hill. Behind it is the Gellért Hill Cave Church, set inside a natural cave system formed by thermal springs. Pauline monks enlarged the cave, and the church was consecrated in 1926.

💡 Cold War Fact: In 1951 the monks were arrested on Easter Monday and the church was closed, its entrance later sealed behind a thick concrete wall. The church reopened in August 1989, when that wall was torn down.

📷 Photo: “Hungary-2512 – Cave Church” by Dennis G. Jarvis / Wikimedia Commons (CC BY-SA 2.0)

📂Artwork File · Seen Sep 2026 — Communist authorities walled up this church inside Budapest’s Gellért Hill. The full story, with every source

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