The Titanic had a sister ship. Most people don't know her story. The HMHS Britannic was the third Olympic-class liner, built by White Star Line in 1914. After Titanic's disaster, Britannic was designed with enhanced safety features—a double hull, higher watertight bulkheads, and improved lifeboat capacity. But she never carried a single paying passenger. WWI broke out, and she was converted into a hospital ship. On November 21, 1916, while sailing in the Aegean Sea, Britannic struck a mine laid