Henley and Partners\' compiles its latest Visa Restrictions Index identifying the best and worst passports in the world. Getty Images

London-based immigration and citizenship consulting firm, Henley and Partners, has compiled its latest Visa Restrictions Index identifying the best and worst passports in the world. Along with the help of the International Air Transport Association, the firm ranks passports by how easily citizens can travel around the world without visas.

"In today's globalised world, visa restrictions play an important role in controlling the movement of foreign nationals across borders ... Visa requirements are also an expression of the relationships between individual nations, and generally reflect the relations and status of a country within the international community of nations," said Henley and Partners.

According to the 2016 Visa Restrictions Index compiled by the firm, it appears a German passport is the gateway to the world followed by the Swedish passport in second place. With a German passport, citizens can travel to 177 out of 218 countries without requiring a visa while a Swedish passport grants visa-free entry to 176 countries.

The third place was shared by Finland, France, Italy, Spain and the UK. Fourth came Belgium, Denmark and Netherlands. Amongst the worst passport rankings, Iraq came third followed by Pakistan in second place and Afghanistan leading the pack. While Pakistani passport holders can visit 29 countries without needing a visa, Afghan nationals can travel to only 25 countries visa-free.

The new index reflects major changes as the US moved from its first position as the strongest passport in 2014 and 2015 to the fourth position now. "Criteria that a country will consider when considering giving visa-free access to citizens of another country may include diplomatic relationships between the countries, reciprocal visa arrangements, security risks, or risks of violation of visa terms," said a representative of Henley and Partners, reported CNN.

Meanwhile, social media users reacted to the latest passport rankings. One user, identified as Hugo Lucke, tweeted a picture of a German passport and wrote: "This country has the world's best passport (and it's not the U.S.)."