The Coal Exchange, 1904

The Coal Exchange is the room for people who like a story. It is set in 1904 in a counting house off Mount Stuart Square, in the years when more coal left Cardiff than any port on earth, and it is full of real things from the period that Ioan spent two years collecting: a set of brass coal scales, a telegraph sounder, a pneumatic message tube that works, a wall of ledgers. Somebody has forged an entry to ruin a shipping firm, and the proof is in the room.

It is harder than the Night Safe because it asks you to read: dates, weights, ship names and a clerk's handwriting that does not quite match. Teams that split up and shout across the room do well; teams that work in silence do not. Three players is the minimum because there are two places that need two people at once.

About a third of teams escape, and the record is 41 minutes 50 seconds. It is our most popular room for team building, because it rewards people who listen to each other, and it is the one the history teachers book.

What is included

• Sixty minutes in a Victorian counting house built from real period pieces
• A working telegraph, pneumatic tube and coal scales
• A game master on the cameras and the radio throughout
• Three free clues on the walkie-talkie
• A team photograph with your time, emailed that evening
• Three to six players

What it costs

From £78 for three to £114 for six, any day, with 10 per cent off before 4pm Monday to Thursday. Sixty minutes; three players minimum. The booking page works out the total and the price a head for your group; the rooms page shows every free slot today and tomorrow.