But which one rules them all?
Turkey and the Central African Republic revoked their visa-free status to U.S. passport holders, recently.
"While Singapore quietly climbed the ranks, the USA passport has fallen down since President Donald Trump took office", Arton Capital said in a statement. The U.S. passport grants holders the ability to travel visa-free to 154 countries.
The new Singapore biometric passport design will feature new visa page designs as well as additional security features, said the Immigration & Checkpoints Authority (ICA) in a statement on Thursday (Oct 26).
According to Arton Capital, this is the first time an Asian country has had the most powerful passport in the world.
This left the United States with a score of 154 and an index ranking of sixth, the same as Malaysia, Ireland and Canada, and behind 18 other passports.
But while Singapore may have been climbing the ranks, possibly due to its strong diplomatic relations and foreign policy, the United States has been struggling since President Donald Trump took office.
How does the Index work?.
Passports of 193 United Nations member countries and six territories - ROC Taiwan, Macao (SAR China), Hong Kong (SAR China), Kosovo, Palestinian Territory and the Vatican - are considered for the index.
So which passports offer the least mobility?
The vote came after Trump refused to allow visa-free travel to members of five European Union countries: Croatia, Cyprus, Poland, Romania and Bulgaria.
So which is the world's most powerful passport?
Germany now holds the spot for the second-most powerful passport at 158, closely followed by Sweden and South Korea at 157.
But, how does the index, developed by global financial advisory firm Arton Capital, work and why does India fare so poorly?
The methodology used to determine the rankings varies.
In 2015, the United States tied for first place with the United Kingdom; previous year, it slipped to fourth place.
In 2015, the US held the list's top spot, tied only with the United Kingdom. At rank 94, Afghanistan's passport is at the absolute bottom. Spain and Italy tied for third, with Ireland rounding out the top five.