Protesters gathered underneath Rio de Janeiro's famed Sugarloaf Mountain earlier this week to protest construction of four cable lines that will carry tourists over the surrounding forest.

The cables, commonly known as zip lines, will carry individuals connected to them by safety harnesses at least 755 meters over the forest to the nearby peak of Urca Hill at speeds of 100 kilometers an hour.

But demonstrators who gathered near Sugarloaf Mountain Sunday say the zip lines will cause environmental damage to the mountain and the surrounding area. Opponents are also concerned the zip lines will lead to an expansion of the visitors center at Sugarloaf’s summit. An online petition against the zip lines has collected more than 11,000 signatures.

Sugarloaf, known in Portuguese as Pao de Acucar, attracts hundreds of thousands of visitors each who take cable cars to the peak to take in breathtaking views of Rio’s famed beaches and the iconic Christ the Redeemer statue. UNESCO ((the U.N.’s Educational, Scientific and Cultural Organization)) named Sugarloaf a World Heritage Site in 2012.

Parque Bondinho, the company that operates the 110-year-old cable car system, is installing the four zip lines. It says the lines will have limited impact on the environment, even as it brings in even more tourists to Rio. The company says it has obtained all necessary permits for the project.

The zip lines are scheduled to be completed by the middle of this year.

Some information for this report came from The Associated Press, Agence France-Presse.