Marianas Trench Marine National Monument comprises parts of the Mariana Trench with Sirena Deep, the world's second deepest point at about 35,000 ft (11,000 m), 21 submarine volcanic sites and surrounding waters, and three of the northernmost Mariana Islands. This is the area where the Pacific Plate is subducted (i.e., thrust) beneath the smaller Mariana Plate, creating different geological formations, including a mud volcano, volcanoes that emit liquid CO2, and hydrothermal vents. The islands and atolls are home to coral reefs with rich ecosystems while the Trench is home to many unusual and still undiscovered species. In some areas, communities that are based on photosynthesis and chemosynthesis coexist. Were you familiar with Marianas Trench Marine National Monument before this survey?

Marine Protected Areas of American Samoa are the next nomination which comprises the National Marine Sanctuary of American Samoa and the Rose Atoll Marine National Monument with the Rose Atoll National Wildlife Refuge. The area contains pristine tropical coral reefs which support high biodiversity. Some of the corals have demonstrated resilience to coral bleaching. There are seamounts and a hydrothermal vent which support communities of deep-sea organisms. Rose Atoll (pictured) is an important refuge for giant clams. Have you ever visited American Samoa?

The Big Bend National Park comprises parts of the Chihuahuan Desert, mountains, and the area around the Rio Grande (a view at the Santa Elena Canyon pictured). It is home to desert flora and fauna, with cooler and wetter mountains acting like "sky islands" which are covered by relic forest of trees such as Arizona pine, Douglas fir, and Arizona cypress. The area is also rich in fossils from the past 130 million years. The Cretaceous–Paleogene boundary is visible in the strata, and furthermore, evidence of the tsunami caused by the Chicxulub impactor. The most famous fossil found in the park is the Quetzalcoatlus, the largest discovered pterosaur. Have you ever been to Big Bend National Park?

There are 22 World Heritage Sites in Canada, with a further 10 on the tentative list. The Virginia Falls at Nahanni National Park is the pictured image. Are you interested in more surveys about World Heritage Sites from Canada or other countries?