You’ve probably seen the video. A camera lens glides into a teardrop-shaped hole in a wall of books, and suddenly, the floor drops away into a bottomless pit of literature while the ceiling vanishes into a sky of paper. It’s the "Infinity Book Tower" in Prague, and honestly, it’s one of those rare internet-famous spots that actually looks like the photos.
But here’s the thing: most people calling it a "tower" or a "tunnel" are technically wrong.
The sculpture is actually titled Idiom. It’s the work of Slovak artist Matej Krén, and it’s been sitting in the foyer of the Prague Municipal Library since 1998. Back then, long before TikTok algorithms started dictating travel itineraries, it was just a quiet, clever piece of installation art. Now? It’s a viral sensation that sometimes has a 45-minute queue just to peek inside for twenty seconds.
What is the Infinity Book Tower, really?
Basically, Idiom is a cylindrical column built from roughly 8,000 books.
Krén didn't just stack them randomly. They’re interlaced like bricks, creating a self-supporting structure that reaches from the floor to the ceiling. The real "magic" happens because of two mirrors—one on the floor and one on the ceiling inside the hollow center.
When you lean your head into the opening, the mirrors reflect the interior of the book stack over and over. It creates a perfect optical illusion of an infinite well. It’s meant to symbolize the "infinity of knowledge," which is a bit on the nose for a library, but it works. Interestingly, Krén didn't use brand-new books. He used discarded, donated, or "saved" books, meaning the tower is literally built from stories that people were done with.
Where to find it (and how to avoid the crowd)
You’ll find it inside the Central Library of the Municipal Library of Prague (Městská knihovna v Praze). It’s located at Mariánské náměstí 98/1, which is incredibly central—just a short walk from Old Town Square and the Klementinum.
- Monday: 1:00 PM – 8:00 PM
- Tuesday to Friday: 9:00 AM – 8:00 PM
- Saturday: 1:00 PM – 8:00 PM
- Sunday: Closed
Pro tip: Do not show up at 1:00 PM on a Monday expecting to be first in line. That’s when everyone else has the same idea. Honestly, if you want to avoid the "influencer" rush, try a random Tuesday or Wednesday morning right when they open at 9:00 AM.
The library staff has become a bit overwhelmed by the sudden fame of the sculpture. They’ve actually had to set up stanchions and separate entrances because tourists were blocking the regular library patrons who were just trying to, you know, return a book on gardening.
The "Science" connection and weird facts
Believe it or not, this thing is famous in the academic world too. In January 2011, the Infinity Book Tower actually made the cover of Science magazine.
It wasn't because of the art, per se, but because it’s such a perfect visual representation of a "well of knowledge."
Another detail people miss: you can’t actually take the books out. People always ask if they can pull one from the middle like a game of Jenga. Please don't. The whole thing is structurally sound but sensitive. It’s never been officially revealed exactly what (if any) adhesive or internal support keeps the books from shifting, but the library is very strict about the "no touching" rule.
Is it worth the wait?
If the line is out the door, maybe not. It’s a cool optical illusion, but at the end of the day, it’s a stack of books and two mirrors.
However, the building itself is a masterpiece. Since you're already there, walk past the tower and look at the Art Deco interior. The ceiling in the central hall has beautiful geometric decorations by František Kysela, and there are stained glass windows that most tourists ignore while they're busy editing their reels.
If you're a real book lover, the library offers a one-day "visitor" pass for a few crowns that lets you into the actual reading rooms. It’s quiet, smells like old paper, and feels significantly more "Prague" than the crowded foyer.
How to get the perfect photo
If you are going for the shot, here is the expert way to do it:
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- Turn off your flash. Seriously. If the flash hits those mirrors, you’ll just get a giant white blob in the center of your photo and ruin the infinite effect.
- Use a wide-angle lens. If your phone has a 0.5x setting, use it. The opening (the "tear") is narrow, and a standard lens won't capture the scale of the "drop" into the floor.
- Hold the phone inside. Don't just stand back. Carefully move your hand into the opening so the camera is centered.
Actionable Next Steps
If you're planning to visit the infinity book tower in Prague, keep these three things in mind to make the trip actually enjoyable:
- Check the local holidays. The library closes for many Czech public holidays, and the queue on the days surrounding these is usually brutal.
- Combine it with the Klementinum. It’s literally right across the street. Most people do the Klementinum tour (the Baroque library) and then pop into the Municipal Library for the Idiom sculpture.
- Bring a backup plan. If the line for Idiom is longer than 30 minutes, walk five minutes north into the Jewish Quarter (Josefov) instead. You can always come back an hour before the library closes when the crowds usually thin out.