The US election campaign came to an end last night. Obama closed his candidacy in the state of Iowa, where he began his journey to the White House in the 2008 elections. Meanwhile, Romney chose Ohio, a state that the Republicans have always won when they acceded to the presidency.
It now remains to be seen whether voters will reflect what polls indicate: a tight race, in which Obama has a small lead.
The outcome may not be known until late Tuesday, as the counting process is very slow due to the size of the country and time zone differences. The first polling stations opened on the East Coast and will close almost a day later in Hawaii.