People take photos of a rainbow arching above Moscow's Red Square after a heavy rain on May 22, 2013. (Xinhua/Jiang Kehong)

Photo taken on May 22, 2013 shows a view of Moscow city after a heavy rain in late afternoon. (Xinhua/Jiang Kehong)

A rainbow arches is seen above Moscow's Red Square after a heavy rain on May 22, 2013. (Xinhua/Jiang Kehong)

Photo taken on May 22, 2013 shows a view of Moscow city after a heavy rain in late afternoon. (Xinhua/Jiang Kehong)

A rainbow arches is seen above Moscow's Red Square after a heavy rain on May 22, 2013. (Xinhua/Jiang Kehong)