Civil War Unknowns Monument The Civil War Unknowns Monument is a burial vault and memorial honoring unidentified dead from the American Civil War . It is located in the grounds of Arlington House , The Robert E . Lee Memorial , at Arlington National Cemetery in Arlington , Virginia , in the United States . It was designed by Quartermaster General Montgomery C . Meigs and constructed in 1865 in a former tree and flower garden . Many sources often incorrectly state that the monument was constructed in the middle of the Lee flower garden ( often mischaracterized as a " rose garden " ) . However , the monument is just west of the flower garden , in what was once a grove of oak and elm trees . History of the site . Construction of Arlington House and " the Grove " . In 1778 , John Parke Custis purchased an tract of forested land on the Potomac River north of the town of Alexandria , Virginia . This land became the Arlington Estate . John Custis died in September 1781 , and in 1799 his son , George Washington Parke Custis ( " G . W . P . " ) — step - grandson of George Washington — inherited the site . G . W . P Custis and his wife , Mary , moved onto the estate , and between 1802 and 1814 they constructed Arlington House . The Custises extensively developed the site . Much of the steep slope to the east of the house became a cultivated English landscape park , while a large flower garden with an arbor was constructed and planted south of the house . To the west of Arlington House , tall grass and low native plants led down a slope into a natural area of close - growing trees the Custises called " the Grove . " About to the west of the flower garden , " the Grove " contained tall elm and oak trees which formed a canopy . An informal flower garden was planted beneath the trees and maintained by the Custis daughters . It is not clear when " the Grove " began to be developed , but it was under way by at least 1853 . G . W . P . ' s daughter , Mary Anna Randolph Custis , married Robert E . Lee , an impoverished lieutenant in the United States Army , in June 1831 . The Lees took up residence at Arlington House . Mary Custis died in 1853 , and Mary Custis Lee had her buried in " the Grove " . G . W . P . Custis died in October 1857 , and he was buried next to his wife in Arlington Forest near " the Grove " . Cemetery . Arlington Estate ' s history changed forever with the outbreak of the American Civil War . Robert E . Lee resigned from the United States Army on April 20 , 1861 , and took command of Virginia ' s armed forces on April 23 . Armed forces loyal to the United States ( " Union " forces ) realized that artillery placed on the heights of the estate would be able to shell the city of Washington at will . Realizing Union forces were likely to seize her home , Mary Custis Lee packed up most of her belongings and fled to her family estate at Ravensworth on May 17 . On May 24 , Union troops occupied Arlington Estate and Arlington House . On July 16 , 1862 , the United States Congress passed legislation authorizing the U . S . federal government to purchase land for national cemeteries for military dead , and put the U . S . Army Quartermaster General in charge of this program . The Soldiers ' Home in nearby Washington , D . C . , and the Alexandria Cemetery were the primary burying grounds for war dead in the D . C . area , but by late 1863 both cemeteries were full . In May 1864 , large numbers of Union forces died in the Battle of the Wilderness . Quartermaster General Montgomery C . Meigs ordered that an examination of eligible sites be made for the establishment for a large new national military cemetery . Within weeks , his staff reported that Arlington Estate was the most suitable property in the area . The property was high and free from floods ( which might unearth graves ) , it had a view of the District of Columbia , and it was aesthetically pleasing . It was also the home of the leader of the armed forces of the Confederate States of America , and denying Robert E . Lee use of his home after the war was a valuable political consideration . Although the first military burial at Arlington had been made on May 13 , Meigs did not authorize establishment of burials until June 15 , 1864 . Although most burials initially occurred near the freedmen ' s cemetery in the northeast corner of the estate , Meigs ordered in mid - June 1864 that burials commence immediately on the grounds of Arlington House . The first officer burial had occurred next to the main flower garden on May 17 , but with Meigs ' order another 44 officers were buried along the southern and eastern sides of this area within a month . In December 1865 , Robert E . Lee ' s brother , Sydney Smith Lee , visited Arlington House and observed that the house could be made livable again if the graves around the flower garden were removed . Meigs hated Lee for betraying the Union , and ordered that more burials occur near the house in order to make it politically impossible for disinterment to occur . Design and construction of the memorial . By 1865 , most of " the Grove " had been lost . Its flower beds and paths had been trampled out of existence by troops and pack animals , and some of its trees had been cut down . That year , Meigs decided to build a monument to Civil War dead in the center of " the Grove " . U . S . Army troops were dispatched to investigate every battlefield within a radius of the city of Washington , D . C . The bodies of 2 , 111 Union and Confederate dead were collected , most of them from the battlefields of First and Second Bull Run as well as the Union army ' s retreat along the Rappahannock River ( which occurred after both battles ) . Some of the dead had been interred on the battlefield , but most were full or partial remains discovered unburied on the field of battle . None were identifiable . Although Meigs had not intended to collect the remains of Confederate war dead , the inability to identify remains meant that both Union and Confederate dead were interred below the cenotaph . U . S . Army engineers chopped down the trees in eastern half of " the Grove " , leaving only a small copse to the west . They dug a circular pit about wide and deep into the earth . The walls and floor were lined with brick , and it was segmented it into compartments with mortared brick walls . Into each compartment were placed a different body part : skulls , legs , arms , ribs , etc . The vault was half full by the time it was ready for sealing in September 1866 . The vault was sealed with concrete and soil . Meigs designed a tall , long , wide grey granite and concrete cenotaph to rest on top of the burial vault . The cenotaph consisted of two long light grey granite slabs , with the shorter ends formed by sandwiching a smaller slab between the longer two . On the west face was an inscription describing the number of dead in the vault below , and honoring the " unknowns of the Civil War " . Originally , a Rodman gun was placed on each corner , and a pyramid of shot adorned the center of the lid . A circular walk , centered from the center of the memorial , provided access . A walk led east to the flower garden , and another west to a road . Sod was laid around the memorial , and planting beds filled with annual plant s emplaced . Changes to the memorial since 1865 . By 1893 , the original monument had been radically changed . The ornate sarcophagus walls were replaced with plainer ones , although the inscription had been retained . The lid was replaced by one modeled after the Ark of the Covenant described in the Book of Exodus in the Hebrew Bible . The Rodman guns were placed muzzle - down into the earth , and the large pyramid of shot removed from the lid . Four small pyramids of shot were placed on either side of the east and west pathways leading to the memorial . The memorial was also raised off the earth onto a slightly larger base of rough - hewn dark grey granite blocks mortared together . This base is three stones high , or about . A second base of large light grey granite slabs about high was placed on top of the first base . A third base , consisting of a single light grey granite slab , was installed above the second base . This third base was slightly smaller than the first two , but slightly larger than the memorial itself . Four light grey granite sections about high sat atop the original sides , decorated with pilaster s . Like the walls of the sarcophagus , these consisted of two long , unbroken sections with smaller sections inserted between them at the ends . These sections were mortised , so that all four sections appear to meet at the corners . A slightly larger light grey granite base flared out above the pilaster section . Unlike the lower section , longer sections were sandwiched between the end sections . ( This enables friction to help tie the monument together . ) The new cover of the sarcophagus consisted of a single large light grey granite slab . Twenty - two bas - relief stars inside circles were added above the lip of the lid . Four stylized , partial fleur - de - lis faced outward at each corner . The top of the lid was rounded . The entire monument was about high at the uppermost portion of the lid . The Civil War Unknowns Monument was the inspiration for Montgomery Meigs ' own tomb , also located at Arlington National Cemetery . Meigs erected the sarcophagus over the grave of his wife , and he himself was buried there in 1892 .