What was the world's first passenger submarine?

Auguste Piccard (PX-8) was an underwater submarine. This was designed by Jacques Piccard. It was the world's first passenger submarine, built for Expo-64. The first immersion took place in Le Bouveret on 27th February, 1964. It had a total of 45 Plexiglass portholes (40 capacity).

Auguste Piccard achieved 1,100 dives (150 metres depth) in Lake Geneva with 33,000 visitors in 1964 and 1965. The ride charge was CHF40. From 1969 to 1984, it achieved scientific and industrial observation dives in the Gulf of Mexico ( an ocean basin and a marginal sea of the Atlantic Ocean). The submarine was also engaged in exploring Lake Geneva with companions F-A Forel, Mir-1, and Mir-2. The submarine is currently on display at the Swiss Museum of Transport in Lucerine (a city in central Switzerland).