Jerusalem is a coveted burial spot, but the ancient city is running out of space to bury the dead. In May, the Washington Post reported that the Jerusalem Jewish Community Burial Society had teamed with a construction group to bore beneath a mountain in the city’s largest cemetery, Har Hamenuchot, and create a massive underground necropolis that will house 22,000 crypts. The plan is to create burial spaces arranged floor-to-ceiling in a network of intersecting tunnels—a little like the ones that first graced the Middle East thousands of years ago. 

Today there are catacombs open for visits around the world, and seven of the most beautiful and historically fascinating are listed below. Note that while the world is full of underground passageways—from the 20,000 square feet of tunnels beneath City Market in Indianapolis (formerly cold storage space) to the vast and only recently re-discovered underground city in Cappadocia—these catacombs have all been used in accordance with the word’s primary definition: burial of the dead. 

1. Rome Catacombs 

Catacombs originated in the Middle East about 6000 years ago and spread to Rome with Jewish migration. Early Christians modeled their burial practices on Jewish customs, although they were forced by Roman rules to bury outside the city limits. Since land was expensive, they went underground, digging an estimated 375 miles of tunnels through Rome's soft volcanic tuff, and building networks of rooms lined with rectangular niches called loculi. Later, more complex tombs included cubical (small rooms that served as a family tomb) and arcosolia (large niches with an arch over the opening, also used for families). Both were often decorated with religious frescos, gold medallions, statues, and other art. The beauty wasn’t just for the dead but for the living, who congregated there to share funeral meals and mark death anniversaries. (The idea that persecuted Christians secretly worshipped there, however, is a Romantic-era legend.)

By the early 5th century, barbarians had invaded Rome and began ransacking the tombs, so the remains of interred saints and martyrs were moved to more secure locations in churches around the city. The catacombs were forgotten for centuries, until miners accidentally rediscovered one under the Via Salaria in 1578. That set off a rush for relics (of dubious provenance) that made the gold rush look like a calm stroll. Today, Rome’s 40-odd catacombs have been stripped of bodies, but the ancient frescoes and winding passageways make them well worth a visit.

2. Paris Catacombs

They weren't the first, but the Paris catacombs might be the most famous in the world, and little can compete with them for sheer macabre glamor. Created by the Romans as limestone quarries to build the city above, their current use dates from the late 18th century, when overcrowded cemeteries around the city sparked public health concerns. (One of the worst offenders was Saints-Innocents, in use for almost a millennium and overflowing with corpses, which wasn’t so great considering its proximity to the popular Les Halles market). Starting in the late 18th century, officials took charge of the situation by relocating the bones—from an estimated six to seven million people—to the former quarries, which were specially blessed and consecrated for that purpose.

The catacombs were opened as a public curiosity in the 19th century, and today visitors can see the bones piled into artful arrangements. (One design is shaped like a keg, another like a heart.) Other attractions include an underground spring, a sepulchral lamp, sculptures created by a quarryman, and special exhibits. Only part of the roughly 200 feet of tunnels is open to the public, although that hasn't stopped intrepid urban explorers, artists, and thieves from journeying to the off-limits sections. In 2004, Parisian police discovered a secret cinema set up inside one area, complete with a bar.

3. Catacombs of Kom el Shoqafa

A series of tombs tunneled into the bedrock beneath Alexandria starting in the second century, the catacombs of Kom el Shoqafa ("Mound of Shards") were forgotten until 1900, when a donkey fell into an access shaft. Today the three levels of catacombs are open for visits, and include several giant stone coffins as well as carvings, statues, and other archeological details melding Roman, Greek, and Egyptian styles. On the second level is the Hall of Caracalla, said to contain the remains of young Christian men (and at least one horse) massacred by Caracalla in AD 215.

4. Palermo Capuchin Catacombs

In the 16th century, the Capuchin church in Palermo, Sicily, began outgrowing its cemetery and the monks got the idea of embalming their dead brethren and putting them on show in the catacombs instead. At first only friars got this special treatment, but the practice caught on and local notables began asking for the honor in their wills. Roughly 12,000 people have since been embalmed and arranged for display according to demographic—the categories include Men, Women, Virgins, Children, Priests, Monks, and Professionals. Burials didn't stop until the 1920s, and one of the most famous inhabitants is also among the last—the beautiful Rosalie Lombardo.

5. Rabat Catacombs, Malta

Beneath the modern city of Rabat, Malta (once the ancient Roman town of Melite) lies an extensive system of rock-hewn underground tombs dating from the fourth to the ninth century AD. Unlike most other catacombs throughout the Mediterranean—and indeed the world—the tunnels were used to bury Jews, Christians, and pagans, without noticeable divisions among the groups.

Features include large tables used for ceremonial meals commemorating the dead and canopied burial chambers, some of which have been inscribed with illustrations and messages (archeologists are still working to interpret the site). Major catacomb complexes in Rabat include those of St. Paul, St. Agatha and Tad-Dejr.

6. St. Stephen's Cathedral, Vienna

The mother church of the Roman Catholic Archdiocese of Vienna, St. Stephen's Cathedral is one of the most important buildings in the city, known for its gorgeous multi-colored tile roof (and for being the site of Vivaldi's funeral). But fewer tourists visit the crypt, where the remains of more than 11,000 people lie.

Although most of the current cathedral dates to the 14th century, the crypt originated after an outbreak of the bubonic plague in the 1730s, when cemeteries around Vienna were emptied in an effort to stem the tide of the disease. Many of the skeletons were piled into neat rows, skulls on top, although visitors to some areas will also see disorganized piles of bones. In one section, the ducal crypt, the organs of princes, queens, and emperors are stored—including Hapsburg Queen Maria Teresa's stomach.

7. Brno Ossuary

A routine archeological dig as part of a construction project in 2001 led to an unexpected discovery in Brno, the Czech Republic—a long-forgotten underground charnel house crammed with skeletons. An estimated 50,000 sets of remains had been stuffed beneath St. Jacob's Square during the 17th and 18th centuries, originally stacked in neat rows but later jumbled by water and mud. The site opened for public viewing in June 2012, and today it’s the second-largest (known) ossuary in Europe, after the Paris catacombs.