The island of Nauru is one of the world's smallest countries. Located northeast of Australia in the Pacific Ocean, it's just 21 square kilometers in size.
As sea levels around the world rise, Nauru's future is at risk. But as a small country, it doesn't have the resources to defend itself from the water.
So to raise money, the island is selling citizenship for $105,000.
Most of Nauru is uninhabitable due to nearly 100 years of mining, which left behind a barren landscape. As a result, nearly all of the island's 12,500 people live along the coast — right in the path of rising seas.
The government says the money earned from passport sales will go toward relocating 90% of the population to higher ground, and building a new community there.
Most of these new passport holders will probably never visit Nauru, according to Kirstin Surak, a professor at the London School of Economics.
But as a Nauru passport gives visa-free access to 89 countries, including the UK and Singapore, getting citizenship may give people more freedom to travel and live internationally. For those with weaker passports, this can be especially valuable, Surak told CNN.
Nauru had a similar passport program in the mid-1990s, but it was discovered that criminals were using Nauru passports to enter other countries under false identities.
The Nauru government promises stricter background checks this time, and anyone with a criminal history will not be able to get citizenship. And anyone from countries the United Nations considers "high risk," such as Russia or North Korea, will not be allowed to apply.
The island expects to earn $5.6 million in the first year, and aims to reach $42 million a year from the passport program.