This 18K yellow gold timepiece represents a valuable piece of history. That’s how best to describe this unique, square-shaped IWC watch. We haven’t come across another one like it in 18K yellow gold, making it not just rare but potentially one of a kind.

What makes this watch even more special is that IWC has traced its sale back to August 14, 1941. This was the very same day as the historic Atlantic Conference & Charter was signed, a joint declaration made by U.S. President Franklin D. Roosevelt and British Prime Minister Winston Churchill.

Inside, the watch features the IWC Cal. 62 hand-wound movement, an impressive piece of craftsmanship for its time. The dial is a deep, beautiful black, accentuated by elegant gold details. At the 6 o’clock position, you’ll find a small subdial.

The case measures 26x26mm (excluding the crown and lugs), with a lug-to-lug length of 34mm. Considering its age—an impressive 83 years—this watch remains in remarkable condition. Take a look at the photos!