Disappointed visitors to Newgrange on the winter solstice had their view from the inner chamber blocked when a snow storm stopped the sunlight entering the chamber as it does every year.
It was a dramatic moment as there was also a lunar eclipse for the first time in 450 years, but the disappointed guests could only stare at a darkening sky and snow flurries.
The ancient Celts had built the burial tomb so that light shines through the chamber at the winter solstice every year -- a fact only discovered in 1967.
The last time there was an eclipse at the winter solstice was 450 years ago when Irish pirate chieftain Grace O’Malley was on the high seas.
It will not occur again for another 200 years.
Just 50 people were allowed in to the inner chamber, drawn in a lottery after 25,000 had applied.
American Danielle Lacava (24), from Pittsburgh, was one of the lucky ones. She came to Ireland with her brother Chris.
"We never thought about saying 'forget it' -- this was one of those things you just can't pass up," she said.
Christa Schunke a Christian Community priest from Germany, said she was just happy to be there. "It was beautiful -- I have never been touched by light in that way before," she said.
"This is the new year of the old Irish calendar," archaeologist Sam Moore told the irish Independent. "The event marks the rebuilding of the sun -- the days get longer from this point. It is a time of renewal and hope."