Coastal & marine 16. Great Barrier Reef (Australia) — largest coral reef system 17. Ha Long Bay (Vietnam) — limestone karsts rising from the sea 18. Cliffs of Moher (Ireland) — dramatic coastal cliffs 19. The Twelve Apostles (Australia) — limestone stacks on the Great Ocean Road

Unique geological & atmospheric phenomena 24. Northern Lights / Aurora Borealis (Arctic regions) — polar aurora displays 25. Mount Roraima & Tepuis (Venezuela/Brazil/Guyana) — tabletop plateaus with endemic life 26. Pamukkale travertine terraces (Turkey) — white thermal terraces

Islands, archipelagos & coastal ecosystems 33. Galápagos Islands (Ecuador) — evolutionary significance and endemic fauna 34. Palau Rock Islands (Palau) — marine lakes and pristine reefs

Unique color & mineral landscapes 30. Salar de Uyuni (Bolivia) — largest salt flat, reflective mirror effect 31. Danakil Depression (Ethiopia) — hydrothermal fields, colorful mineral deposits 32. Great Blue Hole (Belize) — (see #29) — included for diving significance

Karst, sinkholes & caverns 27. Son Doong Cave (Vietnam) — world’s largest known cave chamber 28. Cenotes of Yucatán (Mexico) — sinkholes/underwater caves 29. Blue Hole (Belize) — large marine sinkhole for diving

Canyons, rock formations & deserts 7. Grand Canyon (USA) — stratified canyon vistas 8. Zhangjiajie (China) — sandstone pillars and forested peaks 9. Uluru (Australia) — monolith with cultural significance 10. Wadi Rum (Jordan) — desert sandstone landscapes and canyons