Tucked away in the heart of the City, just opposite the exclusive Walbrook Club, lies one of London’s most unexpected hidden treasures: the ancient Temple of Mithras. Invisible from street level but preserved beneath the towering Bloomberg European headquarters, this Roman sanctuary offers a captivating glimpse into the city’s 2,000-year-old past. And best of all, entry is entirely free to the Lunchtime Tourist.
From Lost River to Rediscovered Temple
Nearly two millennia ago, the Temple of Mithras stood beside the River Walbrook, a waterway that has since vanished beneath concrete and glass. The damp floodplain preserved writing tablets, coins and religious artifacts, leaving archaeologists with a remarkably detailed record of Roman London (Londinium). One of these tablets contains the earliest known written mention of “Londinium,” making it the first documented name for our modern capital.
After its rediscovery in the 1950s, the site lay forgotten beneath offices until financier Michael Bloomberg funded its restoration. Now, a descent down a discreet stairwell transports visitors from the corporate lobby into an extraordinary subterranean world, where history and modern exhibition design merge seamlessly.
Architectural Echoes of a Church
At first glance, the Mithraeum’s layout resembles a medieval church rather than a pagan temple. Seated between two artfully lit aisles, seven stone columns once supported low wooden beams, creating a narrow nave that led to a semi-circular apse. Archaeologists believe this curved end may have functioned as a lustral basin or baptismal font, though its exact purpose remains debated.
The number seven appears significant: seven columns, seven levels of initiation, and seven planetary gods in Mithraic cosmology. This suggests a structured mystery cult where members—soldiers, merchants and perhaps even high-ranking officials—progressed through ritual stages to achieve spiritual insight.
Bloomberg SPACE: Art Meets Antiquity
Before descending into the temple itself, visitors pause in Bloomberg SPACE, an airy exhibition area showcasing contemporary art alongside a display of Roman artifacts. Here, glass cases house oil-wax writing tablets, broken pottery, chiselled altars and votive offerings—each item telling a fragment of daily life in ancient Londinium.
This gallery moment allows guests to absorb the artifacts’ context before experiencing the immersive sound-and-light presentation below. Every 20 minutes, a six-minute show unfolds in the dimly lit temple chamber, conjuring the legend of Mithras slaying the cosmic bull in a cave illuminated by flickering torches and accompanied by a haunting musical score.
Descent into the Mithraic Mystery
As you step down the stairs into the cool, echoing chamber, the transition feels almost ceremonial. The enclosed, windowless environment evokes the original cave setting where Roman initiates once gathered. Suspended between past and present, you can almost sense the hushed whispers of worshippers and the rhythmic chants that would have accompanied secret rites.
The audio-visual production layers narration with atmospheric sound effects, guiding the audience through key moments of the myth and allowing each visitor to draw their own conclusions about the cult’s significance and its place in Roman religious life.
Access and Booking Details
The Temple of Mithras is open to the public from Tuesday to Saturday, with entry free of charge. Advance booking is strongly recommended via the Bloomberg Connects app or the official website, as slots fill rapidly and admission is capped to preserve the site’s fragile integrity. Once booked, simply present your e-ticket at the discreet entrance on Walbrook and follow the signage to the exhibition lobby below Bloomberg’s soaring atrium.
Each visit typically lasts 30–45 minutes, including time in the exhibition space, the immersive chamber and a chance to reflect in a quiet garden nearby where plaques recount key details of the temple’s discovery and restoration.
A Legacy Beneath the City
Few Londoners realise that beneath buzzing streets and gleaming skyscrapers lies a place of ancient mystery and brotherhood. The Temple of Mithras stands as a testament to the city’s layers of history, from Roman civic centre to global financial hub. For the Lunchtime Tourist, it offers a rare opportunity to step out of the modern world and into a sanctuary that once united Romans of differing ranks—and which still demands quiet awe today.