Three very old boats were discovered recently in different parts of the world. The oldest was in Serbia. Earlier this month, archaeologists unearthed a ship from the Roman empire, dating back to the third century, A.D. Archaeologists also found a 200-year-old shipwreck off Mexico’s Caribbean coast. And in the U.S., a storm recently revealed the 100-year-old wreck of a steel boat in Utah’s Great Salt Lake.