Located in northern Ariaona, Grand Canyon National Park is one of the most spectacular     1     (example) of erosion (侵蚀) anywhere in the world.     2    (measure) roughly 277 river miles in length, up to 18 miles in width and a mile deep, it is truly     3     natural wander. For 6 million years, the Grand Canyon has expanded with the help of the mighty Colorado River, and over the past few centuries, people from all over the globe     4    (travel) to gaze out over its red and orange magnificence. Managed by the National Park Service and     5     (official) chosen as a UNESCO World Heritage Site, the Grand Canyon leaves its approximately 6 million visitors per year deeply     6    (impress).

But the Grand Canyon can be very crowded. The South Rim,     7     the Grand Canyon and the well-worn Bright Angel Trail are situated, holds a fascination     8     many sightseers and hikers. It is on this side that you'll find the most tourists. For a break from the crowds,     9     (head) to the North Rim. This is the place for backwoods camping and hardcore hiking. For an unforgettable view of the canyon, consider     10     (sign) up for a helicopter tour.

There are many scenic spots in the world. Some are the best form of architecture ever built and seen. The Great Wall, Taj Mahal, the Pyramids of Egypt and Petra     1     (actual) prove the point that architecture is an age old art and profession.

Not many people know the only piece of construction that can     2     (see) from the moon is the Great Wall of China,     3     total length built in all dynasties is 21,196.18 kilometers. It is the world’s longest man made structure.

Taj Mahal is a beautiful piece of architecture of all times, which was constructed by     4     (use) materials from all over India and Asia.     5     is believed that over 1,000 elephants were used to transport building materials. It     6     (take) the efforts of 22,000 laborers, painters, artists and stonecutters to shape Taj Mahal.

One of the best     7     (place) to experience traditional architecture is Egypt. The Pyramids of Egypt make us extremely amazed at how     8     (create) the architects in ancient times were and what efforts were made by ancient people.

Petra is another place     9     (visit) great structures. This ancient city was the capital of the Arab kingdom of the Nabateans,     10     trade center. The city is famous for water tunnels and stone structures carved in the rock.