The Eiffel Tower is tightening security by adding bulletproof glass and a metal fence to help protect the monument and visitors from potential terrorist attacks. The glass panels ― nearly 10 feet high and more than 2 inches thick ― are being installed at the north and south ends of the Paris monument, NPR reported. A metal fence has been installed on the east and west sides to prevent vehicles from breaching the site.

The $40 million security project began last year and is to be completed in mid-July.

The Société d’Exploitation de la Tour Eiffel, which manages the tower, “decided to build a new perimeter around the Eiffel Tower to increase the security,” Bernard Gaudillere, president of the organization, told ABC News.

The glass panels and metal fence replace temporary barriers that were installed in 2016 after a series of terror attacks in France.