Grand Canyon vistas also can be viewed by air. Visitors sometimes opt to hire a helicopter or airplane for a narrated journey from the sky. These tours provide quite a different perspective and operate out of Grand Canyon Airport. They fly in designated airspace so as not to conflict with other visitors in the park.
While some are quite content with the pace of a visit on foot， many yearn for the thrill of a rafting trip down the Colorado River，s rapids. Some of the most exhilaratingexhilarating adj.令人喜欢的， 爽快的， 使人愉快的 in the country， these rapids can be traversed through tours given by outfitters who use rubber inflatable rafts or wooden dories. Boating on the Colorado is the only access to some of the canyon，s most remote and pristinepristine adj.质朴的 hiking trails.
Riverrafting trips typically take 6 to 8 days on motorized trips and 10 to 14 days on oarpowered trips. (Longer trips are also available.) Canyon trips typically start at Lees Ferry near Page. Shorter trips lasting 4 to 9 days， in the upper and lower portions of the canyon are available， exchanging midway at Phantom Ranch. Such split trips require hiking out of the canyon after the upper half or into the canyon to start the lower half. Oneday trips are offered in the western Grand Canyon on the Hualapai Reservation and halfday trips operate from the base of the Glen Canyon Dam at Page.
At the more remote North Rim， visitors access the canyon via the town of Jacob Lake. Because its elevation is 1，000 feet higher than the South Rim， the road to the North Rim closes in midOctober and reopens in midMay. North Rim facilities， therefore， are only open from midMay to midOctober. Those who visit during the summer months will find a campgroundcampground n.野营地， 露营场所， general store， camping facilities and a historic lodge. Though millions journey to the park each year， only a tenth of these visit the more remote North Rim. Visitors who want to experience its lesscrowded atmosphere should still plan ahead， however， since park facilities can sometimes reach maximum capacity. Additional lodging and supplies are available in Jacob Lake， 45 miles north.
For a leisurely day trip to the canyon， schedule a train ride on the Grand Canyon Railway. The vintage train starts at Williams， “The Gateway to the Grand Canyon，” which is about a halfhour，s drive west from Flagstaff. Passengers enjoy strolling musicians and a mock train robbery on the ride and then arrive at the canyon for a threeandahalfhour layover of sightseeing and shopping at the South Rim.
Returning on the Grand Canyon Railway in the afternoon， visitors can continue to explore Northern Arizona，s beauty in Williams， historic district - including Route 66. Sports enthusiastsenthusiast n.热心家， 狂热者 will enjoy Williams， Gary Panks - designed， 18hole championship golf course in summer， and a family ski area just outside of town in the winter. Fishing and camping are also plentiful among the pines in the surrounding area.
Route 66 continues west of Williams through the communities of Ash Fork and Seligman. Restaurants and shops still showcase 1950sstyle memorabilia， when the highway was in its glory. Twentyfive miles west of Seligman， visitors can tour the Grand Canyon Caverns， a living limestone cave 210 feet down. Two of the Caverns， main rooms are each as large as a football field.
Niagara Falls尼亚加拉瀑布
在美国的自然景观中，尼亚加拉大瀑布最为壮观。尼亚加拉瀑布是世界着名的大瀑布之一，位在北美的伊利湖和安大略湖间的尼亚加拉河上。瀑布总宽度1240米，平均落差51米。它被一个名叫山羊岛的岛屿分流，在断崖上形成两个宽大的水帘；处在美国境内的叫亚美利亚瀑布，宽度约 300米；在加拿大一边呈半环形，叫马蹄形瀑布，宽度约 800米。此瀑布自1678年被一个法国传教士发现以来，一直成为美加两国的重要旅游胜地，旅游设施也不断完善，在美国一侧划为尼加拉公园，是美国最早的国家公园。在加拿大一侧划为维多利亚女王公园。瀑布四方建有四个高塔，游人可乘电梯登塔了望瀑布全景，也可下地下隧道，钻入大瀑布脚下，倾听瀑布下落时洪钟雷鸣般的响声，北美从1846年开始组织了乘船观光活动。人们在船上披着雨衣在瀑布下泻的最近处观看水雾彩虹。着名作家狄更斯在观看这世界奇观后这样写道：“瀑布那样色彩缤纷、奇特，令人悠然神往，我仿佛脱离了尘世，看到了天堂。”
尼亚加拉瀑布其实是两块，美国分到一块小的，加拿大分到一块大的，叫做horseshoe waterfall。
水势的确壮观，轰然直坠如玉城雪岭。从岸上俯视河水，河面宽，水流湍急，但隔着白茫茫的水雾也看得出清澈无比，有如琉璃，河底的巨石都历历可见。瀑布奔腾而咆哮，稍走近就一身湿透。
Niagara Falls is a group of massivemassive adj.厚重的， 大块的， 魁伟的， 结实的 waterfalls located on the Niagara River in eastern North America， on the border between the United States and Canada. The Falls comprise three separate waterfalls： Horseshoe Falls (sometimes called Canadian Falls)， American Falls， and the smaller， adjacent Bridal Veil Falls. While not exceptionally high， Niagara Falls is very wide， and is by far the most voluminousvoluminous adj.卷数多的， 大部分的， 着书多的， 容积大的， 体积大的， 丰满的， 长篇的， 庞大的 waterfall in North America.
Niagara Falls is renowned for its beauty， and is both a valuable source of hydroelectric power and a challengingchallenging adj.引起挑战性兴趣的， 挑逗的 project for environmental preservation. A popular tourist site for over a century， the Falls are shared between the twin cities of Niagara Falls， New York and Niagara Falls， Ontario.
Formation of the Falls