The number of high net-worth Turkish citizens looking for a second passport through investment has increased 100 percent over the last three years, a recent report has revealed. But what does "citizenship by investment" mean? Anadolu Agency (AA) asked experts and searched for the countries that offer the chance of a second passport - if someone has the cash.

The term, also known as "economic citizenship" or "investment immigration," is realized when a country gives citizenship in return for bringing business or purchasing real estate. According to Tolga Habali, director of Henley & Partners Turkey - an international company that advises clients on the best places to invest and get a passport - a second citizenship is a growing need. "The world has experienced the globalization of goods and services as well as the globalization of capital; today we have seen the globalization of human beings, which makes second citizenship a must," Habali told AA. He added that, according to Henley & Partners' index, applications for second-citizenship programs increased 100 percent in Turkey over the last three years. "There are many good reasons why you should apply for a second citizenship program," Habali said.

The programs are aimed at wealthy individuals and families who want to secure themselves and enjoy freedom of travel, tax benefits and investments as well as business opportunities in offshore markets. According to Habali, the motivations of individuals in Turkey are no different: "Consequently, it is a big gain to create alternatives in every aspect."

Visa-free travel is the key reason for the increasing number of applications for citizenship by investment programs. Turkey has been struggling with the European Schengen and United States visa requirements of its citizens for many years. However, Turkish citizens have never been so close to benefiting from visa-free travel to Europe's Schengen area - possibly starting in June 2016 as part of recent talks between Turkey and the European Union.

Experts across the world also say instability and security issues are key factors motivating people to seek citizenship through investment. Many countries, especially in the Middle East and Europe, are struggling with a surge in refugees and terrorism. Due to wars both in Iraq and Syria, there is concern over increasing crime, terrorism, foreign fighters and other extremist organizations both in Turkey and Europe. Additionally, more than 1 million refugees arrived in Europe last year, fleeing Syria, Iraq and parts of Africa.

Released by Arton Capital, a global financial advisory firm for investments, a 2014 report found that around 60 percent of all wealthy second-citizenship applicants come from countries in the Middle East. According to Habali, the countries that have legal economic citizenship programs are Malta, Cyprus and Austria in Europe and Antigua & Barbuda, St. Kitts & Nevis, Dominica, Grenada and St. Lucia in the Caribbean.

However, Habali emphasized that contrary to general belief, many countries like Canada, the U.S., the U.K., Spain and Portugal do not offer citizenship by investment programs. "We need to make a distinction here. The aforementioned countries have only immigrant investor programs offering applicants immediate permanent resident status, citizenship or a temporary residence permit. You can only get citizenship [from these countries] if you receive a migration and residence permit or live in those countries for many years," he said.

The 2014 Arton Capital report shows that the average net worth of a second-citizenship applicant is well above the global average for wealthy individuals. Applicants have an average net worth of $205 million, compared to the global ultra-high net worth' average of $135 million, the report said.