The Plutonium of Hierapolis
The gate to the underworld — where priests defied death
📱 1 to 10 phones · 1 team per phone · Independent codes
Eight trials, a deadly breath, a secret of death
Beneath the Temple of Apollo, a cave exhaled deadly vapours the priests seemed to control — they emerged alive while animals perished inside.
Strabo, the 1st-century BC geographer, describes the Plutonium as an opening in the rock from which vapours escape so dense that birds flying over it fall dead. Yet the eunuch-priests of Cybele entered unharmed, proving — they claimed — their bond with the underworld deities. In 2018, Italian archaeologists solved the mystery: volcanic CO₂ accumulates at ground level during the night but dissipates at height. The priests, standing, breathed above the deadly layer. But they also had another secret, carved in eight ritual trials that only initiates could decipher.
« "I released sparrows there that fell dead at once. But the Galli enter and emerge unharmed." »— — Strabo, Geography, book XIII
The Plutonium, ancient gateway to the underworld
The Plutonium of Hierapolis is one of the rare places in the ancient world explicitly identified as an entrance to the underworld. The cave, located beneath the Temple of Apollo, emitted carbon dioxide vapours from the volcanic activity of the Pamukkale fault. The eunuch-priests (Galli) of the goddess Cybele organised public demonstrations: they entered the cave and emerged alive, while bulls and birds succumbed inside.
The geographer Dio Cassius notes that the priests "held their breath or possessed an antidote". The 2018 discovery by archaeologist Hardy Pfanz shows that CO₂ concentration varies by time: deadly at ground level at night (up to 91%), it decreases at the height of a standing man during the day. Ceremonies took place at dawn, when the gas was at its lowest, and the smaller animals breathed in the deadly layer.
A game, a guided tour and a heritage guide — all in one
You're not just buying an escape game. You're carrying a living guide — historical anecdotes, forgotten legends, key monuments, hidden architecture — unfolding as you go.
At each stop, places ordinary guides miss — secret façades, sculpted crests, alleys steeped in history.
Every riddle is rooted in a real historical fact or local legend. You leave with dozens of stories to tell.
Learn to read buildings — flamboyant Gothic, Baroque, Art Deco — like a real art historian, while having fun.
Walk through the city like a novel's character — every alley becomes a stage, every square a theatre.
A voice walks with you at every step, tells the story of each place, reads clues, adds a cinematic feel.
Keep access to the guide & game for 1 year. Come back any time, share it with friends.
« You will not leave this city the way you entered it. »
How does it work?
Explore the city on foot solving puzzles based on real historical facts. No locked room — the city is your playground.
No app to download. Play directly from your browser. Guided step by step, at your own pace.
One purchase per phone is enough. Play with family, friends or as a couple — everyone participates.
Point your phone at the façade: a historical character appears and speaks to you in your language. Golden letters magically write themselves on the wall to reveal the puzzle answer.
Stuck? Progressive personalised hints. The character repeats the puzzle on demand — at your own pace.
French, English, German, Spanish, Italian + 27 other languages auto-translated by AI.
Want to go deeper?
Places tied to your adventure — optional entries, totally up to you · per person
The Route
8 stages through the city
The gameplay: AR, camera, hidden clues
At each stop, open your phone camera: an augmented reality character appears on the façade and speaks your language. Hunt the clue — it materializes as golden letters on the real wall or floats in front of you. When you find it, the phone vibrates, an AR chest opens and reveals your answer fragment. 8 stops, 8 clues to find with the camera, 1 final code.
The stops on your route are a surprise. You'll discover them one by one, guided by your phone, starting from the meeting point.
How does it work with a group?
One phone = one team. Pick the number at checkout (1 to 10).
Solo, or a group sharing the screen. One team, one code.
Family, couple, or 2-3 teams competing. Each phone has its own code and its own score.
Friends, bachelor/bachelorette, small office outing — each their own code, each plays at their own pace. Tiered pricing then €6 flat per phone from the 6th.
- ✓All codes are independent — play at the same time OR separately, each team advances at its own pace.
- ✓Leaderboard between your teams + global game leaderboard — each score appears in the public ranking.
- ✓More than 10 phones or need a personalized quest? Discover custom tours.
Ready to live this adventure?
Get my code · 12€No calendar booking. Code sent immediately by email.
🔒 Secure payment · Code in 5 min · Free cancellation
Practical info
Why this route?
Gate to the underworld
One of the rare ancient accesses to the underworld, scientifically proven.
Science and mystery
The priests' mystery solved in 2018 by science.
Ritual sacrifices
Bulls perished where priests survived.
Pamukkale
Where death had a door and the priests held the key
9 features nobody else has
OddballTrip combines gamified play, augmented reality and AI. All our competitors deliver 1 or 2 of these angles. We deliver all 5.
AR treasure chest
A golden chest floats in front of the monument. Tap → opening animation → reveals a secret message.
AR narrator character
Point your phone at the façade: a knight, witch, monk, sailor, detective or ghost appears full-screen and speaks to you in your language with their dedicated ElevenLabs voice (each character has their own unique voice) — your living guide.
Magic golden letters
At the puzzle climax, golden letters magically write themselves on the real wall — that's the puzzle answer. An unforgettable visual effect.
Written + audio narration
Every puzzle available as text AND voice-over: read at your own pace or listen eyes-free while walking. Great in groups and for accessibility.
360° radar + vibration
A mini-radar shows the target even behind you, and the phone vibrates when you aim in the right direction.
Heritage storytelling
Every puzzle weaves in real historical facts (architecture, era, anecdotes). You learn by playing — like a gamified audioguide.
Progressive AI hints
3 levels of AI-generated help: vibe → where to look → answer format. You're never stuck.
AR selfie memento
At the end of the game, capture a selfie with OddballTrip banner + mascot, shareable on Instagram, TikTok.
Zero app to install
PWA technology: open the link, it plays in your browser. Same quality as an app, no App Store hassle.
Frequently asked questions
Q01Do I need to download an app?
No, never. You get a link, you click, it plays in your browser. That's the point of a PWA: same as an app, without the hassle.
Q02Does it work offline?
GPS yes (handled by your phone). Maps yes (tiles cached). AI and hints need an intermittent 4G connection.
Q03How long does a game take?
1 h 30 to 2 h 30 depending on your pace. The timer runs but only for the leaderboard — you play at your own tempo.
Q04What happens if I'm stuck?
You get 3 levels of hints per puzzle (increasing penalty). If truly stuck, you can skip the step (45-min penalty but you keep going).
Q05What's the age range?
From 12 without an adult, from 6 with an adult reading puzzles. Works for families, couples, friend groups, companies.
Q06What if my city isn't in the catalogue?
Pre-register or contact us — we'll email you as soon as your city is live.
Q07What is augmented reality exactly?
Point your phone at the façade: a historical character appears full-screen and speaks to you in your language. At the puzzle climax, golden letters magically write themselves on the real wall — that's your answer. After each puzzle solved, a treasure chest floats in front of you. Seeing is believing.
Avis des aventuriers
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Your turn to play
Uncover the secret of the priests who defied death in the deadly cave of Hierapolis.
1 purchase = 1 phone. Play several on the same device.
No calendar booking. Code sent immediately by email.
🔒Secure payment · Code in 5 min · Free cancellation
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