PUT-IN-BAY, (AP) -- Engineers say the Perry's Victory and International Peace Memorial needs a more effective waterproofing system to prevent further deterioration.
The monument closed for several months in 2006 when a 500-pound chunk of stone broke off the observation deck.
Engineers found a second loose piece on the 352-foot granite memorial in July 2006 -- a month after the first piece fell 300 feet to the ground.
The monument on South Bass Island is 1 of Lake Erie's most recognizable sights. It opened in 1915 to commemorate Commodore Oliver Hazard Perry's victory over the British in the Battle of Lake Erie in 1813 during the War of 1812.
Kathy Schneider of the National Park Service says the monument could crumble in the next 10 years if permanent repairs aren't done.