The Baltic Sea's trove of shipwrecks has preserved all kinds of history—much of it about war—and recently sparked fears of a fresh conflict in Europe. Bordered by Scandinavia, Finland, the Baltics, the North European Plain, and accessible by Russia, one sliver of the sea contains about 1,000 known shipwreck objects, maritime expert Thomas Dehling tells Deutsche Welle. He's referring to what slumbers in 6,000-square-miles of "German waters," which he says represent not even a tenth of the full sea. "Many of the objects aren't large shipwrecks, but much smaller, or partially submerged [ones]," he says. "We still find 10 to 15 objects every year that we didn't know about before." Most are from World War I and II, but not all: A Swedish three-masted warship called the Mars went down in 1564 while battling the Danes and may have been cursed by its own cannons, National Geographic reported last year.
Discovered in 2011, the warship sank when its cannons overheated and exploded during battle; legend says it was cursed because Swedish kings repurposed church bells to build the cannons. In another Baltic find, 168 bottles of perfectly preserved 19th-century French champagne were discovered on a sunken schooner near Finland, Smithsonian reports. "It was incredible," says a scientist of the bubbly that later sold for up to $100,000 a bottle. Then last year, Sweden saw its Cold War fears revived—and concerns about modern Russia heightened—when said it spotted a foreign sub in its waters. Sweden now says a Russian sub may have indeed been found in the Baltic ... but the wreckage is thought to be that of a WWI vessel that likely went down almost 100 years ago. (Read about a "sickening" shipwreck find in the Arctic.)