Where and what is Jeju Island?

(CNN) -- The ferry that capsized on April 16 with 459 passengers onboard off the coast of South Korea was headed to Jeju Island, the country's biggest island and one of South Korea's nine provinces.

The island is South Korea's most popular holiday island, attracting 10 million visitors in 2013, according to government statistics.

More than 70% of visitors are domestic travelers, seeking out what has become known as the "Hawaii of South Korea."

The island is well known for natural wonders, including waterfalls, white sand beaches and a dormant volcano -- South Korea's highest mountain -- at the center of the island.

MORE: Insider guide to Jeju Island

April to June is prime time for school field trips to Jeju Island, say Korea Tourism officials.

It's estimated that more than 300 high school students were on the ferry, traveling from the city of Ansan to Jeju for a four-day excursion.

In 2007, UNESCO inscribed "Jeju Volcanic Island and Lava Tubes" onto its list of World Heritage Sites, highlighting Geomunoreum, "regarded as the finest lava tube system of caves anywhere, with its multicoloured carbonate roofs and floors, and dark-coloured lava walls."

Jeju Island is one of the world's New 7 Wonders of Nature.

In 2011, Jeju Island was named one of the New 7 Wonders of Nature.

Jeju is also home to haenyo divers, also known as "Korean mermaids."

These women, often elderly, have taken up diving the ocean for abalone, sea urchin, octopus and seaweed.

The volcanic landscape -- 90% of Jeju's surface is basalt -- has given rise to other attractions, such as grandfather stones (dolharubang), massive phallic statues that resemble Easter Island's moai.

The island is also home to the Loveland theme park, dedicated to sex and eroticism.

In September 2013, Jeju Island was in the news after a Chinese luxury cruise ship was detained for issues related to a legal proceeding over outstanding lease payments.

Quick facts

• Located 64 kilometers south of the Korean Peninsula, Jeju is one of nine South Korean provinces and is the country's most popular holiday island.

• Jeju Island is 1,848 square kilometers and has a population of about 600,000 people.

• In 2013, more than 10 million tourists visited Jeju according to government statistics. More than 70% were domestic visitors.

• The capital of the island is Jeju City.

• Jeju's city of Seogwipo co-hosted the 2002 Korea/Japan FIFA World Cup.

• Jeju is 434 kilometers south of Seoul. The flight time between the two locations is just over an hour. Jeju International Airport services regular direct flights to cities such as Tokyo, Osaka, Beijing and Shanghai.