No one thought that the RMS Titanic would sink on its first time at sea. But in 1912, the ship hit an iceberg and sank during the night. No one knew exactly where it had sunk. Even if someone had known, it was 12,500 feet (3.8 km) underwater. To search for the Titanic so deep in the water seemed impossible. But, 73 years later, Dr. Robert Ballard thought he had found a way to go that deep.
In 1985, Ballard set out to find the Titanic. He would use an unmanned submarine（无人驾驶的潜水艇）called Argo. Ballard's research team controlled it from a ship on the surface. Argo had video cameras and lights on it. This let Ballard see the ocean floor.
Argo searched for signs of the Titanic. For many days and nights, Ballard and his teammates found nothing but sand and sea life. Time was running out. Ballard had only four days left before he had to return his boat. He knew this would be his only chance. Then, Ballard was awakened by one of his men. It was just after one o'clock in the morning. He rushed to the control room. On a screen was the view of one of the Titanic's boilers. They had found it!
Argo took amazing pictures of the ship. Ballard and his teammates found that the huge ship was in pieces. The debris was spread across one square mile (2.6 km2) of the ocean floor. They saw teacups, bottles, shoes, and other belongings（所有物）of the passengers.
During his career, Ballard has made more than 100 trips underwater. He has done much to teach children about the oceans. But, he will always be thought of as the man who found the Titanic.
