"... Pierre Charles L’Enfant. The L’Enfant Plan generated many urban nodes calling for the erection of monuments. Yet Washington is the only major Western capital that lacks a triumphal arch.... The triumphal arch originally appeared in Rome in the second century B.C., well before the fall of the Republic. The Romans... modified the monumental gateways of their Etruscan neighbors as free-standing structures and articulated them with the classical architectural forms—columns, friezes, cornices—developed by the Greeks.... It’s worth noting that, contrary to widespread belief, there is no record of a Roman arch being built for its honoree’s triumphal procession... To be sure, numerous victory arches were erected along the processional via triumphalis that led up to the Temple of Jupiter on the Capitoline in Rome. But hundreds of arches were also erected in many other venues.... They could celebrate the construction of new roads, bridges, ports, aqueducts, or city walls—sometimes being atavistically embedded in the latter, sometimes standing slightly in front of them. They marked entrances to forums (civic centers), sacred precincts, and important public venues such as the Circus Maximus in Rome...."
From an article by Catesby Leigh in City Journal, published last December,
"Trump Should Erect an Arch for America’s 250th/His plans to mark the semiquincentennial in 2026 offer an appropriate opportunity to do so in Washington" (City Journal).