Newgrange

Newgrange is a Megalithic Passage Tomb that dates about 5, 000 years old.  It's about an hour north of Dublin on the road to Belfast.  I really enoyed my visit there a few years ago....

This piece of arcitecture pre dates the pyramids of giza.......  it's still waterproof after 4000 years and every year on the winter soltice at sunrise, the sun enters a "window" above the door and illuminates the entire inside... the arictects must have been amazing mathamaticians...........     cannot stress too much how cool and amazing place this is

check this out 

http://www.knowth.com/newgrange.htm