The people of Ukraine are marking the 20th anniversary of the Chernobyl nuclear disaster.
In the capital, Kiev, President Victor Yushchenko placed a bouquet of roses at a memorial by the 'Chernobyl church', where survivors gather every year.
Hundreds of people, each bearing a candle and some with red carnations, filed slowly through the streets of Slavutych, the town built to house the Chernobyl plant's workers after the accident.
At 1.23am local time (9.23pm last night Irish time), about the time of the explosion, a minute of silence was declared. A bell tolled and alarm sirens blared.
The explosion claimed thousands of lives and contaminated large swathes of territory in Ukraine, Belarus and Russia with nuclear fall-out also measured across much of western Europe.
It happened when a test involving Chernobyl's cooling system went wrong. A power surge resulted in water from the cooling system turning to steam, blowing off the roof of the reactor.
A second explosion released 3% of the reactor's radiation.
A soaring cloud spilled radioactive debris into the surrounding area and a radiation cloud drifted across half of Europe.
28 workers died in the immediate explosion while a further 19 died fighting the resultant fire.
Controversy continues over the ultimate death toll.
The UN estimates 4,000 deaths, mainly through cancers, while Greenpeace claims the true death toll could be up to 100,000.
