President Trump, who turned 80 today, will spend this evening hosting an Ultimate Fighting Championship bout on the South Lawn of the White House. A mass media spectacle months in the making, the event has transformed the White House grounds in ways that presidential historians say are unprecedented.

Late last month, construction began on the towering superstructure known as the “Claw” that now sits complete on the South Lawn, taller than the White House itself. White House staff members were told to work from home on Friday while the U.F.C. put finishing touches on the production, which it estimates cost more than $60 million to put on. Fighters are expected to be filmed walking through the Oval Office, out onto the lawn and into the claw, where some 4,000 people will be waiting to watch a total of seven fights.

Much of the White House real estate has been given over to the U.F.C. for this. A crew of motocross stunt riders performed backflips on the South Lawn on Saturday. Another place to watch the fight was set up on the Ellipse, just beyond the White House gates. That space can hold more than 75,000 people.

This fight night is a marketeering extravaganza: The octagonal cage for the fights is plastered with the names of sponsors who paid for their brands to appear with the ultimate backdrop. It’s heavy on crypto and light beer.

All this high-octane, high-budget entertainment from the White House comes as the president is mired in negotiations with Iran, trying again and again to bring an end to the war, which has raised gas prices and lowered his poll numbers.