Starting in 1958 U. S. Navy submarines collected upward-looking sonar profiles, for navigation and defense, and converted the information into estimates of ice thickness.
Black Sea | Mediterranean Sea | Baltic Sea | North Sea | Red Sea | Caspian Sea | Caribbean Sea | Adriatic Sea | Ice-T | Ice Cube | Aegean Sea | South China Sea | Sea of Japan | Ross Ice Shelf | Irish Sea | Westland Sea King | Dead Sea | Arabian Sea | Tyrrhenian Sea | Southend-on-Sea | Ice Hockey World Championships | Ice Age | East China Sea | Ionian Sea | Defenceman (ice hockey) | Bering Sea | White Sea | Vanilla Ice | Kara Sea | First Sea Lord |