Millions of Americans will cast ballots on Tuesday in an Election Day unlike any other, braving the threat of Covid-19 and the potential for violence and intimidation after one of the most polarising presidential races in US history.

In and around polling places across the country, reminders of a 2020 election year shaped by pandemic, civil unrest and bruising political partisanship will greet voters, although more than 90 million ballots have been already submitted in an unprecedented wave of early voting...