Excavation work is set to begin within the next two weeks on a proposed 250-foot triumphal arch monument in Washington, D.C., a project facing a lawsuit from opponents who contend it lacks necessary congressional authorization.

Interior Secretary Doug Burgum announced Thursday that construction would commence on the Great Triumphal Arch and Military Observation Deck, planned for Columbia Island between the Lincoln Memorial and Arlington National Cemetery. Mock-ups depict a white arch with gold detailing, eagles, and a winged Lady Liberty-like figure, inscribed with "ONE NATION UNDER GOD."

"This will be one of the Great Pieces of American Architecture, honoring the history and significance of Arlington Cemetery and befitting the most powerful Capital in the World," Burgum stated on X, formerly Twitter. He defended the project, noting that the idea for a monument has historical precedent and citing arches present in over 70 other major cities. "Now after 125 years of waiting, the most powerful capital in the world will be the home of the most spectacular and beautiful arch of them all!" Burgum added.

The project is being challenged by three veterans and an architectural historian, represented by Nicolas Sansone of the Public Citizen Litigation Group. "We believe that construction cannot and should not proceed apace, and we are prepared to inform the court that it needs to, at this juncture, step in," Sansone told The Associated Press. The lawsuit argues that "congressional authorization is necessary and lacking for this project."

A National Park Service report released last month supports the arch proposal but acknowledges that the project would have "direct and indirect adverse effects on the sight lines of historic properties."

The arch is one of several projects initiated during the Trump administration, which also included renaming the Kennedy Center, adding a new White House ballroom, and refurbishing the Lincoln Memorial Reflecting Pool.