When you think of churches, you probably picture serene sanctuaries bathed in soft light. Yet the world of holy architecture hides some truly bizarre treasures. From bone‑laden crypts to pagan‑infused springs, these ten sites prove that faith can be both awe‑inspiring and downright eerie. Below, the 10 strangest church relics on public display are catalogued in descending order, each with its own spine‑tingling story.
10 Crypt Of The Chiesa Immacolata Concezione
Rome, Italy
This seventeenth‑century sanctuary was commissioned by Cardinal Antonio Barberini, a Capuchin Franciscan who also happened to be the brother of Pope Urban VIII. Designed by the Franciscan friar Michele da Bergamo, the church boasts a host of illustrious tombs and celebrated paintings. Yet its most arresting feature lies deep beneath the floor: five subterranean chapels harboring the remains of roughly 4,000 Capuchin friars and impoverished Romans from the 1600s onward.
Transporting the bones was a logistical feat – 300 trips between 1627 and 1631 moved carriages brimming with skeletal remains into place. Legend holds that the soil covering the crypt’s pavement was sourced from the Holy Land, and a solemn memento mori inscription near the exit declares, “You are what we have been. You will be what we are.”
The ossified assemblage is arranged with artistic flair: mosaics, columns, arches, and floral motifs all fashioned from bone. Distinct crypts exist for specific parts – a Crypt of Skulls, one of Pelvises, another of Leg and Thigh Bones, plus a Crypt of the Resurrection featuring a painting of Jesus summoning Lazarus, and a Crypt of the Three Skeletons, a symbolic diorama reflecting on mortality.
9 Basilica Of Santa Croce In Gerusalemme
Rome, Italy
Also known as Heleniana or Sessoriana, the Basilica of Santa Croce in Gerusalemme rests on what once formed part of a residential complex owned by Emperor Constantine in the third century. The site was originally the Sessorian Palace, built for Constantine’s mother, Helena, and is reputed to rest upon soil she brought back from Jerusalem.
Constantine erected the basilica to enshrine a trove of relics returned from the Holy Land by his mother, especially items linked to the True Cross. Among the macabre collection are three alleged fragments of the Cross – a nail, a segment bearing the famed INRI inscription, and two thorns said to originate from the Crown of Thorns. These artifacts now reside in the Chapel of Relics, crafted by Florestano di Fausto.
Curiously, women may only view these sacred objects once a year, making access a rare privilege for the female faithful.
8 Capela Dos Ossos
Evora, Portugal
Adjacent to the Church of St. Francis in Evora stands the modest Capela dos Ossos. Like several other entries, this chapel is lavishly adorned with human bones. Uniquely, the interior is entirely coated in skulls and skeletal fragments, and if you glance upward you’ll encounter the preserved bodies of a woman and a young boy, suspended from chains and staring down at visitors.
The chapel, dating from the sixteenth century, safeguards roughly 5,000 monks’ remains, exhumed from nearby overcrowded cemeteries. Historically, such bone‑decorated spaces served both pragmatic and spiritual purposes: they provided a solution to burial space shortages, and they acted as stark reminders for the living to contemplate mortality.
A welcoming inscription reads, “Nos ossos que aqui estamos, pelos vossos esperamos” – translated, “We bones that are here, for your bones we wait.”
7 Church Of Santo Stefano Rotondo
Rome, Italy
On Rome’s outskirts, away from the usual tourist throngs, lies the Basilica di Santo Stefano Rotondo al Monte Celio, commonly called Santo Stefano Rotondo. Consecrated by Pope Simplicius between 468 and 483, the church is dedicated to Saint Stephen and was erected atop an ancient Roman mithraeum.
While architecturally modest, the basilica houses a striking series of thirty‑four paintings encircling its interior walls, each depicting the gruesome demise of a Christian martyr. The artworks, commissioned by Pope Gregory XIII in the late sixteenth century, portray torture with a near‑pornographic realism that would make even the hardiest stomach turn.
Charles Dickens famously described the collection, noting, “…a panorama of horror and butchery no man could imagine in his sleep… Grey‑bearded men being boiled, fried, grilled… women having their breasts torn with iron pinchers, their tongues cut out… the mildest subjects.”
6 Aghia Moni Convent
Nafplio, Greece
The Monastery of Aghia Moni, perched just outside Areia near Nafplio, functions today as a Greek Orthodox women’s retreat overseen by the Bishopric of Argolis. Though relatively obscure, the convent is famed for a spring on its grounds that bears unmistakable pagan overtones.
The site is dedicated to Zoodochos Pigi – the “source of life” – and the spring itself is linked to the legendary Kanathos of Greek mythology. Pausanias, the ancient traveler, recorded that in Nauplia there existed a spring called Kanathos where Hera would bathe annually, regaining her maidenhood. This ritual, described as a “holy secret” in the Mysteries honoring Hera, hints at pre‑Christian rites that later fell out of favor with Orthodox practice.
Because of its pagan roots, the spring has largely slipped into obscurity, yet the convent remains a testament to the layered spiritual history of the region.
5 The Barberini Coats Of Arms, St. Peter’s Cathedral
Vatican City
Within St. Peter’s Cathedral, the Baldachin Altar and its bronze canopy – both sculpted by Gianlorenzo Bernini between 1624 and 1633 under Pope Pius VIII – feature a striking series of Barberini family coats of arms. Each shield displays three bees arranged in a triangular pattern on a blue field, topped by a woman’s head.
A close inspection reveals subtle variations across the eight shields, arranged two per column. Some scholars interpret the progression as a symbolic narrative of childbirth, noting the evolving expression of the woman’s face from joy to distress, and the shield’s bulging form culminating in a cherubic visage.
One popular legend suggests the design commemorates a promise by Urban VIII to his niece, Giulia Barberini, to erect an altar in her honor should her labor be successful. Others argue the motif reflects the Church’s earthly struggles, ultimately “delivered” by papal authority, underscoring the Barberini’s influence within the Vatican.
4 Na-Gig Of Kilpeck
Herefordshire, England
Located near the Welsh border, Kilpeck Church (St. Mary and St. David) is a modest Norman‑style, two‑cell structure perched atop an older foundation. Its most infamous feature is a Sheela‑na‑gig – a sculpted corbel depicting a squatting woman with exaggerated genitalia.
Sheela‑na‑gigs appear across England, Ireland, and France, often serving as cautionary or protective symbols. The Kilpeck example, dating to at least the twelfth century, blends grotesque humor with a stark moral warning about sexual sin. While some argue the figures derive from pagan goddess worship, their placement among Christian motifs suggests a medieval didactic purpose.
Over time, such carvings migrated from churches to castles and even flintlock pistols. Male counterparts also existed, and Victorian sensibilities even led to the removal of some corbels deemed indecent, underscoring the enduring tension between sacred art and societal mores.
3 Otranto Cathedral, Tree Of Life Mosaic
Otranto, Italy
Consecrated in 1088, Otranto Cathedral boasts an astonishing floor mosaic commissioned in 1163 by Archbishop Gionata d’Otranto and overseen by the monk Pantaleone, with contributions from local and Norman artisans as well as Tuscan craftsmen. Restored in 1993, the mosaic blankets every square foot of the cathedral’s floor, depicting an intricate “Tree of Life” that sprawls across the interior.
The mosaic’s iconography is a bewildering blend of mythological, religious, and even astronomical symbols. Greek goddesses Diana, Deucalion, and Pyrrha mingle with Arthurian legends, zodiac figures, and scenes from the Golden Bough. Christian motifs such as Adam and Eve, apocalyptic beasts, and the story of Cain and Abel coexist alongside Arabic inscriptions, reflecting a surprisingly eclectic worldview for a medieval Italian cathedral.
Scholars believe the creators were unusually erudite, aiming to encapsulate the totality of contemporary knowledge in stone. The result is a mesmerizing, almost otherworldly tapestry that challenges conventional expectations of sacred art.
2 Otranto Cathedral, The Skull Cathedral
The second reason Otranto Cathedral earns a spot on this list is its macabre “Skull Cathedral.” Adjacent to the main altar lies a chapel whose walls are lined with the skulls of roughly 800 Christian martyrs, displayed behind glass. Some of these relics were also transferred to the Church of Santa Caterina in Formello, Naples.
In 1480, Ottoman Sultan Mehmet II, fresh from conquering Constantinople, set his sights on Italy. After a brief campaign toward Brindisi, he turned to Otranto. The siege culminated on August 14, when Ottoman forces broke through, pillaging the town and offering its male inhabitants a grim choice: convert to Islam or face beheading. The townspeople chose death, resulting in the execution of 800 men on the Hill of the Martyrs (formerly Hill of Minerva).
Antonio Primaldi, the chosen spokesman, was the first to be beheaded. Legend recounts that his headless body stood upright, prompting an executioner to convert on the spot before being slain himself. The sacrifice bought time for King Ferdinand I of Naples to regroup and eventually repel the Ottoman advance, arguably saving Italy and Rome from further conquest. In May 2013, Pope Francis canonized Antonio Primaldi and his fellow martyrs, marking the largest canonization in history.
1 Sedlec Ossuary
Kutna Hora, Czech Republic
Compared to other bone‑filled churches, the Sedlec Ossuary is a true spectacle, housing the remains of at least 40,000 skeletons. Situated in the suburbs of Kutná Hora, just outside Prague, the small chapel became a repository for excess bones after centuries of overcrowding due to its reputation as a holy site (rumored to contain soil from Golgotha) and recurring plague outbreaks.
In 1870, woodcarver František Rint was tasked with organizing the chaos. His solution: a dazzling display of bones throughout the chapel, including a coat of arms for the Schwarzenberg family and a chandelier composed of every human bone imaginable.
Among the macabre décor are angelic and cherubic carvings, bone‑crafted candleholders, and entire walls lined with skulls. Rint even signed his name using bone fragments, ensuring his artistic legacy would endure alongside the skeletal remains.
These ten sites prove that the line between reverence and the uncanny is often thinner than we imagine. Whether you’re drawn by history, art, or the sheer oddity of bone‑adorned sanctuaries, each location offers a unique glimpse into the ways humanity has chosen to memorialize the divine and the dead.