OBERHAUSEN, Germany: The artist Christo has unveiled his latest spectacular creation: a balloon-like installation that fills the inside of a former natural gas storage tank in Germany’s industrial Ruhr region.

An inflatable envelope made of translucent white polyester, Christo’s “Big Air Package” rises 90 meters from the floor of the Gasometer in Oberhausen.

With a diameter of 50 meters and a volume of 177,000 cubic meters, the artwork is the largest-ever inflated frameless envelope and indoor sculpture ever made.

Christo’s structure is kept upright by air fans and visitors enter through airlocks. Christo says the effect is to leave visitors “virtually swimming in light.”

The tank was converted into an exhibition hall after being taken out of service in 1988.

Christo and his late wife, Jeanne-Claude, in 1999 exhibited a wall made of 13,000 colored oil barrels at the Gasometer.

Christo’s “Big Air Package” will be open to the public through Dec. 30.