The United States is home to 10 of the 133 cardinals eligible to vote for the next pope. That's more than any other nation except Italy, home to 17 of the electors who will gather at the Vatican’s Sistine Chapel on Wednesday for the conclave that will choose a successor to Pope Francis.

All of the 133 cardinals expected to take part in the secret conclave to elect a new pope have arrived in Rome, the Vatican said on Monday, with the race to succeed Pope Francis seen as wide open. The conclave will start behind the closed,

While there are a few cardinals seen as front-runners to succeed Pope Francis -- two often mentioned are Italian Cardinal Pietro Parolin and Filipino Cardinal Luis Antonio Tagle -- many of the clerics who will vote have not made up their minds.

There are currently 135 cardinals who are under age 80 and eligible to vote in the conclave, hailing from 71 different countries in the most geographically diverse conclave in history. Already two have formally told the Holy See that they cannot attend for health reasons, bringing the number of men who will enter the Sistine Chapel down to 133.

As more than a billion Catholics around the world await the election of a new pope, all eyes will be on the Sistine Chapel, where 133 cardinals will begin the secretive process known as a conclave.