ON a bluff overlooking the Hudson River, a constant staccato tap echoesat Grant’s Tomb, the granite and marble mausoleum at Riverside Driveand West 122nd Street set off by classical white columns. Hard at workare half a dozen people fitted out in work goggles and armed withchisels and orange buckets of spackle. But it’s not the tomb that theyare tapping away at.

Their focus is an elaborate series of colorful and curvy mosaicbenches that surround the monument. The 17 connected benches, erectedby artists and volunteers in the 1970s in what was described as thelargest public art project in the country, have fallen into disrepair.

Theexquisitely detailed works look as if they would be more at home in afanciful public park in Barcelona, where Antoni Gaudí is the architectmost associated with the city, than surrounding a presidentialmausoleum. But the oddity of their appearance drew tourists to themonument at a moment when it was among the city’s least visited sites.

Now,though, nearly half the benches are chipped, faded or worn bare. Inresponse, more than 40 artists and volunteers have begun restoring thebenches during the last two weeks, replacing damaged tiles with newlydonated ones. The restoration project is being coordinated by CityArts,the nonprofit group that originally commissioned the work.

“It’sa piece of the neighborhood,” said Pedro Silva, a 73-year-oldChilean-born artist and sculptor who oversaw the creation of thebenches and whose artist son, Tony, now leads the restoration project.“It’s a very site-specific piece of art; it wouldn’t make senseanywhere else.”

Sauntering from bench to bench the other day,Mr. Silva pointed out the finer details of the seemingly endless arrayof whimsical images. “There are a lot of stories here,” he said. “Wedon’t want to lose them.”

One bench features an intricatesketch of a police officer giving a ticket to a cabdriver. Other imagesinclude an upside-down circus elephant, penguins and Eskimos on ice,and images from Medieval mythology, like dragons, a princess and acastle.

Mr. Silva recalled the communal spirit that imbued theproject when 2,500 New Yorkers were involved in the construction anddesign of the benches from 1972 to 1974. “We had graffiti artists elbowto elbow with professors from Columbia,” he said.

One of themost popular works is what Mr. Silva calls the lovers’ bench, faded butstill adorned with hearts and flowers and the voluptuous curves of anude couple in repose. Facing the river, the bench is a favoritesunset-viewing spot for young couples.

“The guard tells me many people make use of this bench at night,” Mr. Silva said with a smile. “It serves a purpose.”