If you plan on visiting the National 9/11 Pentagon Memorial, you might want to head over sooner than later.

The memorial will close on Sept. 16 for eight months for construction, less than a week after the 18-year commemoration of the attack, the U.S. Department of Defense announced in an advisory Monday.

Construction on the memorial is mostly focused on lighting repairs. The memorial, which is filled with 184 benches that honor the lives lost when hijacked American Airlines Flight 77 crashed into the Pentagon, has experienced several issues in the past.

Water often seeps beneath the memorial benches and there were recurring lighting system failures, the advisory says. By the time construction is expected to be completed on May 29, 2020, all of the electrical systems at the memorial will be replaced with new bench lighting and a new electrical conduit that feeds power to light fixtures.

The closure will happen in two phases: The memorial bench area will be closed on Sept. 16 until construction is complete. The Memorial Gateway entrance will remain open until Nov. 16, when it’ll also be closed until the project is finished.

You’ll still be able to visit the Pentagon Chapel though, including the 9/11 memorial inside—it won’t be affected by the project.

The new lighting system is meant to “enhance the beauty of the Pentagon Memorial” as well as the visitor experience, the Department of Defense says.