Tourism is thus a growing sector of the economy of Burma. Burma has diverse and varied tourist attractions and is served internationally by numerous airlines via direct flights. Domestic and foreign airlines also operate flights within the country. Cruise ships also dock at Yangon. Overland entry with a border pass is permitted at several border checkpoints. The government requires a valid passport with an entry visa for all tourists and business people. As of May 2010, foreign business visitors from any country can apply for a visa on arrival when passing through Yangon and Mandalay international airports without having to make any prior arrangements with travel agencies. Both the tourist visa and business visa are valid for 28 days, renewable for an additional 14 days for tourism and three months for business. Seeing Burma through a personal tour guide is popular. Travelers can hire guides through travel agencies.