18. Lunar rainbow, Victoria Falls, Zambia

This rare natural phenomenon occurs for three days around the full moon during high-water season at Zambia's most stunning waterfall.

The best "moonbows" tend to occur between April and August, and a great place to view them is on the banks of the Zambezi at Tongabezi just upstream from the heart of the action.

Tongabezi guests stay in thatched lodges and can take canoe safaris, swim in the Devil's Pool, go rafting under the falls and gaze upon the moonbows. From US$485 per person, per night including all meals, drinks, laundry service and activities; tongabezi.com

19. Shubenacadie tidal bore, Canada

The Bay of Fundy in Nova Scotia is home to the highest tides in the world, creating a rare Tidal Bore --- or giant wave --- in the Shubenacadie River.

The tide enters at its widest point and the water piles up as it flows up the bay. At the head of the bay, this advancing tide becomes a wave, varying from a ripple to up to three meters high.

The Shubenacadie River Runners operate Zodiac trips which ride the crest of the tidal surge and on through several sets of natural sand rapids; half-day rafting from US$60 per person; tidalborerafting.com

20. Cape Tribulation, Australia

The lush green coastal strip of Cape Tribulation, the most northerly settlement of Queensland, Australia, is one of the few places where the rainforest meets the sea.

Nowhere else are these two natural side-by-side wonders so accessible to travelers. It's understandable, then, why this is one of the world's finest spots to watch a sunset.

Visitors can rent a four-wheel drive out of Port Douglas, drive to Daintree, take the five-minute ferry crossing across the mangrove-encrusted estuary and brace for an endurance test of a drive, enough to test the suspension of any off-roader.

Once at Cape Tribulation, a variety of boardwalks lead to the shoreline and, at sunset, one of the world's most breathtaking views; experiencequeensland.com

21. Rock face city of Petra, Jordan

This year marks the 200th anniversary of the rediscovery of this former lost city, considered one of the greatest jewels of the Middle East.

Carved into the sheer rock face by the Nabataeans, people who settled here more than 2,000 years ago, this magical rose-red metropolis was a hub for the silk and spice routes in ancient times.

Entrance to the city is through the Siq, a narrow gorge flanked on either side by soaring, 80-meter high cliffs. The colors and rock formations are dazzling, and at the end of the gorge stands the first-century Treasury, with its fabulous carvings.

Movenpick's Resort Petra is located at the entrance to the ancient city, and its roof garden has spectacular views of the Great Rift Valley. Rooms cost from around US$155 per night double, including breakfast; moevenpick-hotels.com

22. Enrosadira, Dolomites, Italy

Sunset in the Dolomites --- which were recently declared a UNESCO World Heritage Site --- is a time when a unique natural phenomenon known as Enrosadira occurs, turning the west-facing rock face flame-red in the dying rays of the sun.

Every evening, these stunning peaks lay on a glorious display of color, starting out bright yellow before turning an intense red that softens to indigo and violet before darkness finally envelops the mountains.

Formed over 250 million years ago, the Dolomites were part of the earth's tropical zone where coral, algae, fish and mollusks collected on the seabed, with magma from volcanic eruptions. After the passing of the Ice Age, rivers, landslides, wind and rain sculpted the valleys, leaving today's spectacular landscape behind.

Relais & Châteaux Gardena Grödnerhof has a prime view of the mountains. Rooms from US$525 per person for three nights; gardena.it; valgardena.it

23. Fairy chimneys, Cappadocia, Turkey

This remote area of Central Turkey is covered in amazing "fairy chimneys" --- volcanic peaks through which it's possible to trek, explore the caves of an underground city or survey from above in a hot air balloon or helicopter.