This Kugel Ball is placed outside of the Casa de las Ciencias ( House of ciences ), in the Parque de Santa Margarita in the center of the A Coruña. According to the Official website of the Casa de las Ciencias it is possible to move this 1500 kilogram granite ball with one hand. I have tried and is confirmed it's possible although it is a little difficult because the ball is very slippery. But you must visit it and try for yourself.
Official website of the Casa de las Ciencias and the Kugel Ball: http://mc2coruna.org
This Kugel Ball is one of those listed on the wikipedia page about the Kugel Ball: https://wikipedia.org
"Solid piece of orbicular granite, which is known as "rapakivi structure", in a perfectly spherical way, because if it wasn't perfect it could not work. It has 97 cm in diameter and an approximate mass of 1500 kg, that is heavier than one car.
The ball is supported on a cylindrical base, with a 75 cm diameter basin that is full of "trapped" water, operating in a closed circuit thanks to a hydraulic pump that works at the same pressure as the ones that supply the houses.
The pressure which the water comes depends on the surface of the exit slit. The smaller this is, the higher the pressure. The weight of the ball tends to make this slit as thin as possible, and a film of whater of tenths of a millimeter thick is enough so that the ball is supported on water."
Translated from Official Flickr page of the Casa de las Ciencias: https://www.flickr.com