Anish Kapoor’s gargantuan sculpture of looping red steel lattices, billed as the tallest sculpture in the U.K. and home to the world’s longest tunnel slide, is £13 million ($15.8 million) in debt. The sculpture, known as the ArcelorMittal Orbit, was built for the 2012 London Olympic Games, and reopened permanently in 2014. It’s located in Queen Elizabeth Olympic Park, roughly four miles from the city center. The work was a pet project of U.K. Prime Minister Boris Johnson, who was mayor of London at the time, and was meant to rival landmarks like the Statue of Liberty and the Eiffel Tower.

The London Legacy Development Corporation (LLDC), which runs the park where the sculpture is located, released numbers revealing the sculpture’s sizeable debt and a steep drop in visitors. Steel magnate Lakshmi Mittal provided a £9.2 million ($11.2 million) loan to help pay for the construction of the sculpture, but this loan has ballooned to £13 million due to the accrual of interest.

Ticket sales to the observation platform and a tunnel slide designed by German artist Carsten Höller were meant to help repay the loan, but low visitor attendance prompted a £58,000 ($70,000) loss in 2018/19 alone. Visitor numbers have dropped from a high of 193,000 in 2016/17, when Höller’s slide was introduced, to 155,000 in 2018/19. An adult ticket currently costs £17.50 ($21) to go to the observation platform and ride the slide, or £12.50 ($15) to only visit the observation platform.

In a 2010 Guardian article discussing the construction of the sculpture, Kapoor said he was partially inspired by the Tower of Babel: