Continue south on 15th Street to Constitution Avenue. From the corner of 15th Street and Constitution,
follow some of the foot paths half a kilometer (three tenths of a mile) to the Washington Monument
Washington Monument -- Site 14
This monument was begun in 1848, but it was not finished until 1885; the change in color about 150 feet
up marks a change in the type of marble used to face the monument. Although it is made of marble, its
smooth, straight shape and the massive blocks used in this monument have minimized the effect of acid
precipitation. Dissolution does occur in a few areas, but the amount of stone material lost from dissolution
is insignificant compared to the mass of the stone.
The straight shape and massive stones in the Washington Monument
minimize the impact of acid precipitation to this important landmark.
Our tour ends here, but there are many more stone buildings and monuments in Washington and in other
cities that may also show the effects of urban pollution and acid precipitation. However, as seen on this
tour, not all of the deterioration of stone buildings is caused by acid rain. To protect our historic stone
buildings and monuments, we need to limit air pollution that contributes to acid rain deterioration, and we
need to develop effective maintenance and preservation procedures that will not further harm the stone.
Map of All Sites on the Tour
[102 K image]
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Maintained by John Watson
Last modified 07.21.97