Niagara Falls

The most famous waterfall — people went over it in a barrel

Niagara isn't very tall (51 m), but it's very powerful: 2,800 tonnes of water a second — 1,000 bathtubs! The falls 'walk' backwards 30 cm every year — the water eats away the rock. In 1901 a 63-year-old teacher, Annie Taylor, went over the falls in a barrel — and survived! At night the falls are lit with coloured lights.

Niagara is 3 waterfalls on the Niagara River between Lakes Erie and Ontario: Horseshoe (Canada, 51 m, 790 m wide), American and Bridal Veil. 2,400–2,800 m³ per second — the most powerful in North America; 50–75% of the water is diverted to hydroelectric plants (4.4 GW; the world's first large hydro plant opened here in 1895 using Nikola Tesla's system). It formed 12,000 years ago as the glaciers retreated; erosion has moved it 11 km upstream (1 m a year, now 30 cm); in 50,000 years it will reach Lake Erie. In 1848 an ice jam stopped the falls for 30 hours. In 1969 the American Falls were 'switched off' for study. 12 million tourists a year. 20% of the Great Lakes' water passes over it.

Fun facts

• In 1848 Niagara stopped for 30 hours — ice blocked the river.
• The falls retreat 30 cm a year — in 50,000 years they'll reach the lake.
• The world's first big power station was built at Niagara — a Tesla project.