Query: A World Heritage site, it is currently under assault from unusually hot ocean temperatures,”

Relevant passages:
Orlando, Florida <=SEP=> Orlando ( -LSB- ɔrˈlændoʊ -RSB- ) is a city in the U.S. state of Florida and the county seat of Orange County . Located in Central Florida , it is the center of the Orlando metropolitan area , which had a population of 2,387,138 , according to U.S. Census Bureau figures released in March 2016 , making it the 24th-largest metropolitan area in the United States , the sixth-largest metropolitan area in the Southern United States , and the third-largest metropolitan area in Florida . As of 2015 , Orlando had an estimated city-proper population of 2,270,934 , making it the 73rd-largest city in the United States , the fourth-largest city in Florida , and the state 's largest inland city .   The City of Orlando is nicknamed `` The City Beautiful , '' and its symbol is the fountain at Lake Eola . Orlando is also known as `` The Theme Park Capital of the World '' and in 2014 its tourist attractions and events drew more than 62 million visitors . The Orlando International Airport ( MCO ) is the thirteenth-busiest airport in the United States and the 29th-busiest in the world . Buddy Dyer is Orlando 's mayor .   As one of the world 's most visited tourist destinations , Orlando 's famous attractions form the backbone of its tourism industry : Walt Disney World , located approximately 21 mi southwest of Downtown Orlando in Bay Lake , opened by the Walt Disney Company in 1971 ; the Universal Orlando Resort , opened in 1999 as a major expansion of Universal Studios Florida . With the exception of Walt Disney World , most major attractions are located along International Drive . The city is also one of the busiest American cities for conferences and conventions ; the Orange County Convention Center is the second-largest convention facility in the United States .   Like other major cities in the Sun Belt , Orlando grew rapidly during the 1980s and into the first decade of the 21st century , mostly due to the success of Walt Disney World , which was opened on October 1 , 1971 . Orlando is home to the University of Central Florida , which is the largest university campus in the United States in terms of enrollment . In 2010 , Orlando was listed as a `` Gamma − '' level of world-city in the World Cities Study Group 's inventory . Orlando ranks as the fourth-most popular American city based on where people want to live according to a 2009 Pew Research Center study .

St. Louis <=SEP=> St. Louis '' ' ( -LSB- seɪnt_ˈluːɪs -RSB- ) is an independent city and major U.S. port in the state of Missouri , built along the western bank of the Mississippi River , on the border with Illinois . The city had an estimated 2016 population of 311,404 , and is the cultural and economic center of the Greater St. Louis area ( home to 2,916,447 people ) , making it the largest metropolitan area in Missouri and the 19th-largest in the United States .   Prior to European settlement , the area was a major regional center of Native American Mississippian culture . The city of St. Louis was founded in 1764 by French fur traders Pierre Laclède and Auguste Chouteau , and named after Louis IX of France . In 1764 , following France 's defeat in the Seven Years ' War , the area was ceded to Spain and retroceded back to France in 1800 . In 1803 , the United States acquired the territory as part of the Louisiana Purchase . During the 19th century , St. Louis developed as a major port on the Mississippi River . In the 1870 Census , St. Louis was ranked as the 4th-largest city in the United States . It separated from St. Louis County in 1877 , becoming an independent city and limiting its own political boundaries . In 1904 , it hosted the Louisiana Purchase Exposition and the Summer Olympics .   The economy of metro St. Louis relies on service , manufacturing , trade , transportation of goods , and tourism . Its metro area is home to major corporations , including Anheuser-Busch , Express Scripts , Centene , Boeing Defense , Emerson , Energizer , Panera , Enterprise , Peabody Energy , Ameren , Ralcorp , Monsanto , Scottrade , Edward Jones , Go Jet , Purina and Sigma-Aldrich . This city has also become known for its growing medical , pharmaceutical and research presence . St. Louis has 2 professional sports teams : the St. Louis Cardinals of Major League Baseball and the St. Louis Blues of the National Hockey League . The city is commonly identified with the 630 ft tall Gateway Arch in Downtown St. Louis .