2. Sanctuary of Madonna della Corona, Italy Perched over 2,000 feet above sea level on Mount Baldo in Italy, this sanctuary overlooking the Valdadige Valley is one of the country's most famous sites dedicated to the Virgin Mary.

3. The Ancient Greek temple of Apollo in Naxos looks like a "star gate"

4. Abuna Yemata Guh, Ethiopia Rising 8,460 feet above the ground, Abuna Yemata Guh (first picture) is arguably the most inaccessible place of worship on earth. It features stunning wall paintings dating back to the 5th century.

5. Church of St. George This church is one of eleven in Ethiopia carved from solid rock, dating to the late 12th or early 13th century AD.

6. Fanjingshan Temples, China These old Buddhist temples, covered with iron tiles to withstand fierce winds, cling to a rocky cliff in the Wuling Mountains, creating a scene that seems almost magical. Reaching them involves a four-hour ascent of over 8,000 steps.

7. Kipina Monastery, Greece This stunning Christian monastery, dedicated to the Virgin Mary, was built with materials from the surrounding mountains.

8. Madonna de Idris, Italy This extraordinary church, carved into solid rock and nestled among the ancient "Sassi di Matera", is over 800 years old.

9. Ad Deir, Petra, Jordan

10. Golden Temple of Laojun Mountain, China Its pavilion with a painted golden roof sits atop one of the peaks of Laojun Mountain, the highest in the Funiu Mountains at 2217 meters.

11. The Expiatory Church of the Sacred Heart of Jesus, Barcelona Located on the summit of Mount Tibidabo in Barcelona, Catalonia, it was built to stop the construction of a Protestant church and a hotel-casino.

12. Las Lajas Sanctuary, Colombia This popular pilgrimage site for Christians from both Colombia and neighboring Ecuador was built in a neo-gothic architectural style between 1916 and 1949.

13. Temple Theater of Monte San Nicola, Italy Rediscovered by chance in 2000 by a paraglider, this 2,100-year-old site features a theater and a temple on the same hill, located 520 meters above sea level.

14. Tiger's Nest, Bhutan First built in 1692 on an 8th-century site, it hangs on a precarious cliff at about 10,240 feet above sea level in Bhutan's Paro Valley.

15. Saint-Michel d'Aiguilhe, France This chapel, dedicated to the Archangel Michael, was constructed in 969 atop a 279-foot volcanic plug and is accessed by 268 steps carved directly into the rock.

16. Chapel of St. Gildas, France This surreal 16th-century chapel is gracefully nestled beneath a towering granite rock.