He was the first person to reach the deepest spot in Lake Superior, a depth of 1333 feet (733 feet below sea level), which is also the lowest point in the United States, on July 30, 1985 while aboard the R/V Seward Johnson with the Johnson Sea Link-II submersible.
Black Sea | Mediterranean Sea | Lyndon B. Johnson | Baltic Sea | North Sea | Red Sea | Caspian Sea | Caribbean Sea | Adriatic Sea | Samuel Johnson | Johnson & Johnson | Dwayne Johnson | Boris Johnson | Johnson | Andrew Johnson | Lyndon B. Johnson Space Center | Aegean Sea | South China Sea | Magic Johnson | Robert Johnson | Sea of Japan | Irish Sea | Westland Sea King | Dead Sea | Arabian Sea | Tyrrhenian Sea | Southend-on-Sea | James Weldon Johnson | Jack Johnson | East China Sea |