Recently, a four-year, $20 million restoration of the Colosseum began with the same purpose - erasing damage caused by pollutants.

"This is a planned four-year phased restoration," Mr. Verre said, that will require some demolition and construction.

The terrace, originally completed in 1864, reopened after a $4.5 million, four-year restoration.

During the four-year restoration, layers of white paint were removed, exposing the church's original brick and brownstone.

A four-year restoration of the mill at a cost of €450,000 was completed in June 2002.

In the mid-1990s, she was the leading private donor to the Conservatory's four-year, comprehensive restoration.

In 1997 the Enid A. Haupt Conservatory reopened after a four-year restoration.

After a four-year restoration, the park, adjacent to the New York Public Library on 42d Street, has reopened.

In 2002, the castle regained its historical value thanks to a four-year restoration, carried out entirely by local workers and craftsmen led by an Argentine family.

In 1907, a major four-year restoration of the palace was begun to restore it to its former state, after which the royal court began to use it regularly again.