Two US presidential candidates, Joe Biden and Donald Trump
The President of the United States is one of the most important and influential people in the world. The impact of the role played by the US President during an international crisis such as war, epidemics or climate change is immense.
That's why every four years, as the US presidential election draws to a close, there's a lot of interest around the world about what the outcome will be.
However, it is also true that many people may not fully understand how this election process works.
Even those of us who work in the BBC's news department - always have to keep in mind how the Electoral College works or what is called 'Battleground State'.
That's why we've created this simple guide to the US presidential election - to the advantage of anyone trying to understand it for the first time.
And those who are experienced, they can also take this opportunity to re-add the things they know.
When is the election? Who are the candidates?
In the United States, elections are held every four years, and voting takes place on the Tuesday after the first Monday in November of that year.
In this election Mr. Trump's rival Democrat Joe Biden's running mate is Kamala Harris
This is how the election date has always been set and as such, the US presidential election is going to be held on November 3 this year.
The politics of the United States are quite different from many other countries. Here are just two of the most influential parties in the political system.
So the president almost always comes from one of these two parties.
However, some smaller political parties - such as the Libertarian, Green, and Independent parties - also sometimes announce presidential nominations
Republican Party
Incumbent President Donald Trump is the Republican candidate - a conservative political party.
Mr. Trump won the 2016 election and is in the running for re-election for another four years.
Donald Trump and his vice president Mike Pence
The Republican Party is also known as the 'Grand Old Party'. More recently, the Republican Party has been pushing for lower tax rates, the right to own a gun, and tougher immigration restrictions.
In general, the support of the Republican Party is stronger in the relatively rural areas of America.
Former Republican presidents include George W. Bush, Ronald Reagan and Richard Nixon.
Democratic Party
The Democratic Party is a liberal political party in US politics. Their candidate in this year's presidential election is Joe Biden.
He is an experienced politician and when Barack Obama was president of the United States for eight years, Mr. Biden was its vice president.
The Democratic Party is known for its liberal positions on issues such as civil rights, immigration, and climate change. They think that the government should play a bigger role in various aspects of people's lives like providing health insurance.
Democratic Party support is strong in urban areas of the United States. Former Democratic presidents include John F. Kennedy, Bill Clinton and Barack Obama.
