UMR's Stonehenge is a partial reconstruction of the original Stonehenge
monument located on Salisbury Plain, west of London. UMR's version of the ancient structure is located on the northwest corner of campus, and was dedicated on June 20, 1984 during the summer solstice. It
features a 50 foot (15 m) diameter ring of 30 stones around a horseshoe of five trilithons through which various sightings of sunrise and sunset can be made. About 160 tons of granite were
used to construct the monument. The rock was cut by UMR's waterjet equipment, which used two waterjets cutting at a pressure of
15,000 pounds per square inch (103 MPa), slicing across the surface just like a conventional saw. The cutter moved at a speed of
about 10 feet per minute (50 mm/s) and cut between one-quarter and one-half inch (6 and 13 mm) on each path.
UMR worked together with artist Edwina Sandys to develop a new way for making deep cuts into granite, and used the method to
create a new sculpture for the campus. The sculpture is known as the Millennium Arch and forms a fitting compliment to an earlier
sculpture, the UMR Stonehenge, which sits on the other end of campus. The Millennium Arch is a single trilithon with a vague
silhouette of a man and a woman on each of its supporting megaliths. The man and the woman are standing several meters from the
arch (and can be seen in the distance between the two silhouettes in the image to the left). The monument is located on 10th
Street, facing Castleman Hall, in Rolla. The project was developed in the High Pressure Waterjet Laboratory
of the Rock Mechanics & Explosive Research Center
at UMR.There are two similar megaliths showing the same silhouette on each side of the sidewalk entrance to the Rock Mechanics &
Explosive Research Center.