Shiun Maru disaster

The Shiun Maru disaster was a ship collision in Japan on 11 May 1955, during a school field trip, killing 168 people.
The Shiun Maru ferry sank in the Seto Inland Sea after colliding with a Japanese National Railways ferry, the Ukō Maru , in thick fog.
A lack of radar onboard contributed to the accident. The victims included 100 students from elementary and junior high schools in Shimane, Hiroshima, Ehime and Kochi prefectures who were on school trips.
The sinking of the Shiun Maru motivated the Japanese government to plan the Great Seto Bridge project, the longest two-tiered bridge system in the world.
The 1955 accident was the fifth such collision of vessels in the Seto Inland Sea since March 1950 and the second accident with fatalities.