Sections of the Berlin Wall in danger of collapse will be restored, authorities said Monday ahead of the 50th anniversary of the closing of the border between East and West Germany. Concrete slabs along Bernauer Strasse, the site of dramatic escape attempts during the Cold War and now of the main Wall memorial, will be repaired by year's end, memorial project director Guenter Schlusche said. "Most of the damage was done by the Wall woodpeckers between 1989 and 1991," Schlusche told AFP, using Berlin slang for the souvenir-hunters who chipped away at the Wall after the border opened on November 9, 1989. "In addition, you have the natural deterioration process." The sections include 175-metre-long (574-foot-long) and 250-metre-long stretches as well as a fence measuring 140 metres -- parts of the massive structure erected by East Germany's communist authorities to stop an exodus of refugees to the West. "They need to be anchored better" to keep them from keeling over, Schlusche said. Initial stabilisation work will be completed by the end of next week ahead of ceremonies marking the sealing of the border on August 13, 1961 that will be led by Chancellor Angela Merkel, who grew up in the communist East. The remaining work, costing a total of 105,000 euros ($151,000), will be finished by the end the year and financed using funds seized from East Germany's ruling party after German reunification in 1990. Nearly 22 years since the Berlin Wall was pulled down in a bloodless revolution, little of the despised structure is still standing as much of it was sold off or carted away in the ensuing euphoria. More than 600 people are thought to have died trying to escape East Germany in the 28 years the Wall was standing.