Archaeologists are uncovering an ancient bridge just outside the Kremlin, the most valuable find to date in the massive dig under Manezh Square.


In a trench in the eastern corner of the huge cavity that used to be Manezh Square, workers are using scoops carefully to scrape away the rubble that covers one gray stone arch, part of what they hope will be a largely intact ancient bridge.


Alexander Veksler, general director of the Archaeological Research Institute and leader of the excavation, said the Voskresensky Bridge, first spotted late last week, probably dates back to the Time of Troubles, a period of upheaval in the early 17th century.


"The Voskresensky Bridge is the most valuable of all structures we have uncovered in the past year and a half under Manezh Square," Veksler said. "It's a monument of architecture, history and archaeology."


Since early 1993 when the work on Manezh Square started, Veksler and his staff, at times aided by Western volunteers, have dug up the remains of brick and wooden homes, a shoe workshop, a bathhouse and pieces of 12th century jewelry.


They are rushing to find as much as they can before the archaeological site is destroyed in one of the city's largest construction projects, a three-story underground shopping mall under much of the square.


Veksler said he had known about the bridge from the start but had waited for construction workers to remove the concrete top layer before uncovering it.


Veksler was not sure how much of the bridge he would find underneath the rubble, but said that it had been one of Moscow's prettiest and most famous overpasses, connecting Tverskaya Ulitsa with Red Square.


The structure, with high arches supported by wooden piles, was covered up when the Neglinka River that ran through Moscow's center was diverted underground in 1818, Veksler said.


The construction project pits the archaeologists against the construction workers, who are already more than half a year behind schedule as more and more valuables appear from under the concrete. The main driveway for the trucks, for instance, had to be closed because it runs right over the bridge, Veksler said.