Although the world is becoming more globalised, there remains a huge disparity in levels of travel freedom between countries.
Visa requirements define and shape individuals' ability to travel across borders.
They also reflect strongly on each country's relationships with others, and will take into account diplomatic relationships between the countries, reciprocal visa arrangements, security risks, and the risks of visa and immigration rules violations.
Releasing its annual 'Visa Restrictions Index' for the last decade the latest 2015 edition, Henley & Partners, a consultancy for residence and citizenship planning, said the UAE has been catapulted into the spotlight as the biggest climber with its dramatic addition of 37 countries and improvement in rank from 55 to 40.
It is also the biggest climber over the ten years of the Visa Restrictions Index, and one of only 22 to have moved up in the rankings over the last year.
Marco Gantenbein, Managing Partner of Henley & Partners in Dubai, said: "Europe, US and Canada, as the world's economic powerhouses, continue to dominate the top 10 as we anticipated. However, it's the performance of the UAE which needs to be applauded for the implied improvement of its international relations, which is very much reflected in the improved ranking in the Index".
Malta, the EU country which runs the world's most successful citizenship-by-investment programme with over 1 billion euros in capital raised since its launch about 18 months ago, further improved its position and now has the 7th best passport in the world.
Two countries have held their position in the top spot with visa-free access to 173 countries out of a possible 218, Germany and the UK. Finland, Sweden and the US all dropped to 2nd place. The four worst passports in the world remain Afghanistan, Iraq, Somalia and Pakistan.
The Last Ten Years: 2006 - 2015
Looking at movement over the last decade highlights other interesting patterns.
European countries are notable for their stability over this time - Belgium, France, Italy, Luxembourg, Spain and Sweden all remain in exactly the same position as 10 years before.
The 'Top Tens' are almost identical, with 30 countries in 2015, compared to 26 ten years before. While Liechtenstein dropped, the Czech Republic, Finland, Hungary, Malta, Slovakia and South Korea all made it into the top ten
The UAE, Taiwan, Albania, Bosnia and Serbia all moved up more than 20 places in the Index over the last ten years, while the biggest drops were experienced by Guinea (-35), Liberia (-36), Sierra Leone (-38) and Bolivia (-40).
The growing importance of investment migration can be seen in steady growth of those countries offering residence and citizenship-by-investment. Those countries with relevant programs continue to perform strongly and all now feature in the top 40 of the Index. It is encouraging to see Malta enter the top 10 after launching its Malta Individual Investor Programme, which is ranked as the best citizenship-by-investment program in the world in the Global Residence and Citizenship Programs 2015 report. Portugal, whose program earned the title as best residence-by-investment programme, is in 4th position this year; and the leading Caribbean country, Antigua and Barbuda, moved up again this year.
The continued development of these countries demonstrates the critical nature of good visa-free access to counties offering investor immigration programs. In turn, this speaks of the importance of due diligence in such programmes, since the reputation of a country's passport and its relationship with other countries is only as good as its newest citizens.
This decade has also seen the launch of the Investment Migration Council, the worldwide association for investor immigration and citizenship-by-investment, highlighting the increasing understanding and acceptance of this important force in globalisation.
The global progress in travel freedom looks set to continue for citizens of all countries.
2015 vs 2014
* UAE was the highest mover, up 15 places and adding 37 to its score. The dramatic climb can be attributed to a new agreement with the EU for visa-free travel to 36 countries including the 26 Schengen area states, which was made public in May this year. As the first Arab country to be granted a European visa waiver, Emirati citizens may travel to a total of 113 countries visa-free, making it the most powerful passport in the Mena region.
* 22 countries moved up in the rankings: Australia, Brazil, Czech Republic, Dominica, Estonia, Grenada, Hungary, Iceland, Latvia, Lithuania, Malta, New Zealand, Norway, Samoa, San Marino, Slovakia, Slovenia, St. Lucia, St. Vincent and the Grenadines, Trinidad and Tobago, UAE and Vanuatu.
* Only two countries remain in the top spot: Germany and the UK (Finland, Sweden and the US all dropped to second place).
* Sierra Leona saw the biggest drop, losing 24 places.
* Guinea and Liberia had the next biggest loss of 21 ranks, then Syria with 16.
* Afghanistan, Eritrea, Ethiopia, Iraq, Kosovo, Nigeria, Somalia and South Sudan all lost 15 places.
* The four worst passports in the world remain Afghanistan, Iraq, Somalia and Pakistan.
Headlines 2015 vs 2006
* The biggest climbers were Albania, Bosnia, Serbia, Taiwan and UAE. Each moving up more than 20 places.
* The two most prominent countries offering citizenship-by-investment programmes in the Caribbean, Antigua and Barbuda and St. Kitts and Nevis, both moved up 13 places.
* Nine countries held exactly the same spot in the rankings as 10 years earlier: Belgium, Brazil, France, Italy, Japan, Luxembourg, Malaysia, Spain and Sweden.
* The biggest drops were felt by Guinea (-35), Liberia (-36), Sierra Leone (-38) and Bolivia (-40).
* The 'Top Ten' are almost identical. 30 countries feature in the top ten ranks in 2015 compared to 26 ten years before.
* Liechtenstein left the top ten, and the Czech Republic, Finland, Hungary, Malta, Slovakia and South Korea all entered it.
Residence and Citizenship-by-Investment Country Performance
* Those countries who offer the most important residence or citizenship-by-investment programmes in the world continue to perform strongly:
* Portugal is 4th with visa-free access to 170 countries.
* Malta climbs to 7th with visa-free access to 167 countries.
* Cyprus is 14th with visa-free access to 158 countries.
* Antigua and Barbuda is 26th with visa-free access to 133 countries.
* All other relevant countries with such programs feature in the top 40, among them Austria, Belgium, Canada, Hong Kong, Monaco, Singapore, Switzerland, the UK and the US.