Hey big spenders This election at least solved the riddle of how to fritter away $1bn

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 111-metre-tall Las Vegas Sphere.

- Richard Luscombe

At a reported $450,000 per day, 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 Harris built since replacing Joe Biden as the Democratic candidate.

Cash-hungry stunts such as this one in the battleground state of Nevada are often targeted at undecided voters in specific swing states and regions. As another example, the campaigns of Harris and Donald Trump, the Republican nominee, booked pricey primetime spots during games involving Pennsylvania's National Football League teams - the Philadelphia Eagles and Pittsburgh Steelers across two nights.