The Ice and Snow World Post Office

In 2018, the world’s largest ice-and-snow park unveiled what may be its most impractical practical invention: a fully functioning mailbox made from blocks of ice. Standing 2.6 meters tall outside a post office carved entirely from frozen river water, the mailbox accepted real postcards. Visitors could buy one, add a special festival stamp, slip it through the icy slot, and send it somewhere considerably warmer.

The mailbox was one small feature of Harbin Ice-Snow World, a temporary city rebuilt each winter beside China’s frozen Songhua River. Founded in 1999, the park has grown into the largest ice-and-snow theme park in the world. The 2024–25 edition covered more than one million square meters and required 300,000 cubic meters of ice and snow.

Much of that ice begins in the Songhua River. Workers carve its frozen surface into enormous rectangular blocks, haul them onto shore, and transport them to the construction site. There, thousands of sculptors, chainsaw operators, ice haulers, and lighting technicians assemble castles, temples, towers, and slides in a matter of weeks. By spring, the entire city disappears back into water. The postcards, presumably, have already reached their destinations.