US election answers the question: how do you spend a billion dollars?

An ad on the 580,000 sq ft Exosphere at the Sphere, on 30 October 2024 in Las Vegas, Nevada. Photograph: Ethan Miller/Getty Images

It was one of the most striking images of the final full week of the presidential election campaign: a giant projection of Kamala Harris’s face on the 516ft-wide, 366ft-tall Las Vegas Sphere.

At a reported $450,000 a day for what is believed to be the first political ad to appear on the futuristic new attraction, it was also one of the most expensive. But even at those rates, it barely made a dent in the staggering election war chest of almost $1bn that Harris has built since replacing Joe Biden at the top of the Democratic ticket this summer.