Older then the pyramids and still holding up fine...of course with a little restoration on the side. The Bend of the Boyne is a fabulous archaelogical site, and is truly one of the highlights of any trip to Ireland.
Despite crowds at the visitors center and tour buses aplenty,the actual site is not at all overrun; with only a limited amount of tourists allowed in each day.
The site itself is composed of three section: Newgrange, Knowth and Dowth. Dowth is not open to the public.
I visited both Newgrange and Knowth, and while I must agree with the reviews below that state that Newgrange is phenomenal, I must put in that Knowth is even better.
Newgrange is composed of a single (albeit, large and spectacular) burial mound, but Knowth has over 40 different burial mounds. Furthermore, the biggest mound at Knowth is 33% larger then that at newgrange. Added to this, Knowth also contains remains of medieval cellars (Souterrains) which are interesting.
But what really sets Knowth apart from anything else is the rock art. Dating from 5000 B.C., there is a phenomenal amount of scribbled swirls, loops, and crescents on the rocks that surround the base of the largest mound. Truly a treasure.
One of the most interesting things about the Bend of the Boyne is the difference between Newgrange and Knowth. Both were restored in the 60s and 70s, but by different archaeologists with different ideas of how it originally looked. The glittering white quartzite that makes up the wall of Newgrange was on the ground lying around the mound. The archaeologist present decided that it must have fallen off the walls and put it back up. At Knowth, a different archaeologist decided the quartzite was used to make a pathway around the mound, and he left it on the ground. Thus there are two visible theories to how the mounds would have looked thousands of years ago,
Overall, this is one of the most worthwhile sites that I have visited and absolutely fascinating (the government tour guides are great too)