CHACO CULTURAL NATIONAL HISTORICAL PARK, N.M. (AP) — The National Park Service is celebrating Chaco Canyon's designation as an International Dark Sky Park.

Officials say the greater Chaco landscape in northwestern New Mexico is one of the last, best places in the U.S. for viewing the night sky.

The celebration starts with a guided walk through Chetro Ketl, one of Chaco's great houses. It covers more than 3 acres and contains several ceremonial structures known as kivas.

There will also be a tour of Pueblo Bonito, the most important site in the canyon, and a discussion about astronomy in the national parks.

The day finishes with telescopes and a star party.

The dark sky designation was made last fall, but the National Park Service had to put off the celebration until now due to the government shutdown.