The city is preparing for the 2024 Olympic and Paralympic Games. 3 events - the triathlon, marathon swimming and para triathlon - will take place in the water. By 2025, 3 quayside pools will also open to the public. Paris has banned swimming in the Seine since 1923. Due to dirty water from the city’s 19th-century sewage system which overflows into the Seine during heavy rains. Now, Paris has built a huge new underground reservoir which can store run-off sewage until the rains stop, protecting the river.