The nuclear trail to Titanic and the intact treasures of the Black Sea. It was the greatest nautical mystery of the 20th Century: the final resting place of Titanic. The nuclear trail to Titanic and the intact treasures of the Black Sea. It was the greatest nautical mystery of the 20th Century: the final resting place of Titanic. The nuclear trail to Titanic and the intact treasures of the Black Sea. It was the greatest nautical mystery of the 20th Century: the final resting place of Titanic. The nuclear trail to Titanic and the intact treasures of the Black Sea. It was the greatest nautical mystery of the 20th Century: the final resting place of Titanic.