It seems that every corner of our world has already been discovered. Someone somewhere has described, photographed, or littered every place. The empty spaces on ancient maps have gradually been filled with detailed information, eliminating the room for marking unknown and dangerous territories. The intense feeling of constant human presence is especially noticeable in cities. In every park and alley, on every bench, someone is either there right now or will be shortly. Hic sunt leones describes inaccessible, forbidden, and forgotten places in Brno. These areas marked “here be lions” hide in the cracks of the perfectly known and mapped urban landscape. The book contains texts, photographs, maps, snippets of dialogues, artefacts, facts, and possibly fiction—all gathered during long-term systematic exploration of these locations. It is a record of the genius loci of places that decay faster than other parts of the city. One hundred books are hidden throughout the city, without any hints or clues. The books themselves thus become part of this seldom-visited urban landscape. Random people will find them over the coming months and years.