Mesa Laboratory, Research structure in Boulder, US.

Mesa Laboratory is the National Center for Atmospheric Research's main building on Table Mesa in Boulder, Colorado. Architect I. M. Pei based its design on the Anasazi cliff dwellings of Mesa Verde, arranging three five-story towers in a village-like layout with a maze-like plan meant to encourage interaction among scientists. The concrete was bush-hammered and mixed with local pinkish aggregate so the complex matches the Flatirons cliffs above it.

In 1960 UCAR named Walter Orr Roberts founding director of NCAR and chose the Table Mesa site; Colorado bought the 565-acre land to keep it undeveloped. I. M. Pei, picked with advice from Pietro Belluschi, designed the lab between 1962 and 1964, moving from a single tower to three five-story towers. Construction began in April 1964 and the building was completed in 1966 and dedicated in 1967.

Pei modelled the complex on the Anasazi cliff dwellings of Mesa Verde, using geometric building shapes and a local pinkish aggregate so the concrete matches the Flatirons above. He also laid the interior out in a maze-like fashion to push scientists into meeting one another. A 68 by 98-inch model of the site that Pei made in the 1960s was donated by him in 2008 and is displayed in a history exhibit.

The Mesa Laboratory is a working research center, not a visitor attraction, so there are no guided tours or public access to the labs. The building stands on Table Mesa below the Flatirons, south of downtown Boulder, and can be viewed from outside; the 1969 Fleischmann Building by Pei sits on the same site.

The concrete exterior was finished with a special bush-hammer technique that mimics the color and texture of the mountain rock surrounding it. This surface treatment makes the building appear as though it grew from the landscape itself.