A car crossing a bridge illuminates the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
People ride a bike among the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
A lamp on a bridge illuminates the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
Cars crossing a bridge illuminate the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
A lamp on a bridge illuminates the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
Swarming mayflies are seen along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
A person holds a mayfly from River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
People take photos of the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) 
A car crossing a bridge illuminates the swarming mayflies along River Danube in Tahitotfalu, some 30 km north from Budapest, Hungary, on Aug. 24, 2013. The improvement of the water quality helped the mayfly species return to River Danube in recent years after four decades of absence. Unlike the more commonly known long-tailed mayfly species on River Tisza, these insects swarm on River Danube at night. (Xinhua/Attila Volgyi) |
|
