Dowth (Irish: Dubhadh ) is a Neolithic passage tomb located in the Boyne Valley, County Meath, Ireland dating from around 2500 to 2000 BC.  It is the second oldest behind Newgrange [ citation needed ] of the three main tombs it Brú na Bóinne World Heritage Site – a landscape of prehistoric monuments including the great passage-tombs of Dowth, Newgrange and Knowth). It is less developed as a tourist attraction than its neighbors, in part because the chamber is much lower, and partly because the decoration is worse. It was partially excavated in 1847, although it was plundered by the Vikings and earlier looters long before that.
The cairn or tumulus is about 85 meters (280 feet) in diameter and 15 meters (50 feet) high,  and surrounded by large kerbstones, some of which are decorated. Quartz Found fallen outside kerbing, indicating that the entrance to the grave surrounded by sparkling white, as Newgrange. Three stone-lined passages leading into the mound from the west.
The long passage crossed by 3 threshold stones and ends in a cross-shaped chamber with a lintelled (not Corbelled as in Newgrange or Knowth) roof.Several of the orthostats (upright stones) of the passage and chamber are decorated with spirals, chevrons, lozenges and rayed circles. On the floor is a single stone basin – slightly worse for wear after 5,000 years. The right arm of the cross leading into another long rectangular chamber with an L-shaped extension entered over a low threshold. This may be the earliest part of the tomb, later in the design of cross grave. It is covered with a 2.4 meter long stone plate containing an oval bullaun (artificial depression). Until recently crossed the tomb was reached by climbing down a ladder in an iron cage, and crawl over loose stones. Now, supply is limited, and all features are guarded by metal grilles.
A curb with bowl-marks, a spiral and a flower like structure marks the entry to the second, less grave – with modern concrete. This has grave some decorated stones, and a single, massive right recess.
At the entrance to the passage of the cross tomb is an early Christian cellar.
Dowth shares a special solar party with neighboring Newgrange during the winter solstice. Martin Brennan, author of the Stars and Stones: Ancient Art and Astronomy Ireland – Thames and Hudson, 1983,  discovered the strange stance over his ten-year study in the Boyne Valley. From November to February the rays of the evening sun reaches into the passage and then the House of Dowth South. During the winter ståndetmot light of the low sun moves along the left side of the passage, then into the circular chamber, where the three stones are lit by the sun.
The convex central stone reflects sunlight into a dark depression, lighting up the decorated stones there. The Rays then subside slowly along the right side of the passage, and after about two hours the sun withdraws from Dowth South.
- ^ Jump up to: abc . Harbison, Peter (1970) Guide to National Monument of Ireland. Gill & Macmillan.
- Jump up ^ Stars and Stones later be published as stones Time: calendars, sundials and Stone Chambers of Ancient Ireland , 1994 [ISBN 978-0-8928-1509-8 or ISBN 0-89281-509-4]