Metallic sediment in the Normandy landing beaches
The first discovery of likely man-made metals in the sands of the Normandy beaches was made in 2011 using a single sample taken from Omaha Beach in 1988. The metal sediment making up 4% of the beach sand was speculatively identified as shrapnel dating to the Normandy Landings.
Source: Wikipedia — Metallic sediment in the Normandy landing beaches (CC BY-SA 4.0)