World watches as US votes in landmark poll

Closeness of the race and the number of states in play raise the likelihood that a victor might not be known on election night

A presidential campaign marked by upheaval and rancor was finally headed for an Election Day finale, as Americans decided whether to send Donald Trump back to the White House or elevate Kamala Harris to the Oval Office.

Voters faced a stark choice between two candidates who have offered drastically different temperaments and visions for the world's largest economy and dominant military power. More than 82 million people voted early. Those casting ballots on Tuesday mostly encountered a smooth process around the country, with isolated reports of some hiccups that regularly happen, including long lines, technical issues and ballot printing errors.