Photo taken on May 22, 2008 shows an aerial view of a corner of a river whose rising water level started to threat the residential zones beside it in Beichuan county, Sichuan province. About 1,800 military personnel were last night trekking toward an expanding quake lake near worst-hit Beichuan county, hoping to blast away its landslide barrier before it bursts and causes a flood. [Xinhua]