The Portland Art Museum celebrated its centennial in 1992, which was marked by successful negotiations to purchase the neighboring Masonic Temple, now known as the Mark Building. The purchase was completed in 1994, the same year that a capital campaign to finance a refurbishment of the Main Building began. This ambitious project included improving the galleries, reinstalling the permanent collection, and equipping the building with a climate control system. The refurbishment allowed the museum to host the most successful exhibition in its history: Imperial Tombs of China, which brought 430,000 visitors to the museum the following year.