Four metal structures pump river water some 30 meters into the air, where it falls freely in liquid curtains 10 to 20 meters wide.

"It's about time and experiencing space," Eliasson (41) said of his creation.

"Water has great potential to be both physical and very elusive, it can be many different things for many different people," he told AFP.

The four waterfalls are located on Governor's Island, under the Brooklyn Bridge, and on two piers. They are visible by day through October 13 from both the Manhattan and Brooklyn sides of the East River.

"The waterfalls are an unbelievable sight. What a beautiful symbol of the energy and vitality that we are bringing back to our waterfront," New York Mayor Michael Bloomberg said at the inauguration ceremony.

Born in Copenhagen in 1967, Eliasson was raised in Denmark and Iceland — he is a dual citizen of the two countries — and divides his time between Berlin and his native city.

Thirty architects, engineers and craftsmen work in his studio, experimenting with installation, sculpture and other large scale projects.

Eliasson believes his waterfalls are enhanced by different kinds of weather.

"I think it's really beautiful if the wind carries the water away," he said.

"Falling water has the ability to show the weather, it shows a lot of things about the wind, the sound, all the senses, not just the eyes," he said.

New York's last major installation was Christo's "The Gates" in February 2005. It featured thousands of orange metal frames draped with saffron fabric along 23 miles of Central Park's pathways.

"The Gates" brought $254-million to the New York economy, city officials said.

The $15.5-million waterfall installation was privately financed. Organizers hope it will bring some $55-million tourist dollars to the city.

Special boat tours have been organised and the city has created special pedestrian and bicycle paths for observing the waterfalls.

"During 'The Gates,' hot dogs vendors in Central Park had the biggest smile of any capitalist in the world! I can tell you the restaurant owner near the Brooklyn Bridge is going to a have a fantastic summer!" Bloomberg enthused.

AFP