Situated on the Han River, Seoul's history stretches back more than 2,000 years when it was founded in 18 BCE by Baekje, one of the Three Kingdoms of Korea. It continued as the capital of Korea under the Joseon Dynasty and the Korean Empire. The Seoul metropolitan area contains four UNESCO World Heritage Sites: Changdeok Palace, Hwaseong Fortress, Jongmyo Shrine and the Royal Tombs of the Joseon Dynasty.[8] Seoul is surrounded by mountains, the tallest being Mt. Bukhan, the world's most visited national park per square foot.[9] Modern landmarks include the iconic N Seoul Tower, Lotte World, the world's second largest indoor theme park,[10] and Moonlight Rainbow Fountain, the world's longest bridge fountain.[11] The birthplace of K-pop and the Korean Wave, Seoul was voted the world's most wanted travel destination by Chinese, Japanese and Thai tourists for three consecutive years in 2009–2011[12] with over 10 million international visitors in 2012.[13