金门大桥是世界著名的桥梁之一

1579年英国探险家FrancisDrake发现了连结太平洋和旧金山的一个海峡，这就是后来的金门。尽管这个名字在1849年的淘金潮以前早就使用，但淘金潮使得金门（进入北加利福尼亚的入口）成了加利福尼亚神秘魅力不可缺少的一部分。早在1872年就讨论过要在金门海峡修建一座大桥的想法，但是直到1937年才在海峡上修了一座悬索桥。金门大桥横跨南北，将旧金山市与Marin县连结起来。花费四年多时间修建的这座桥是世界上最漂亮的结构之一。它已不是世界上最长的悬索桥，但它却是最著名的。金门大桥的巨大桥塔高227米，每根钢索重6412公吨，由27000根钢丝绞成。1933年1月始建，1937年5月首次建成通车。

The orange towers of the Golden Gate Bridge-probably the most beautiful, certainly the most photographed bridge in the world-are visible from almost every point of elevation in San Francisco. The only cleft in Northern California's 600-mile continental wall, for years this mile-wide strait was considered unbridgeable. As much an architectural as an engineering feat, the Golden Gate took only 52 months to design and build, and was opened in 1937. Designed by Joseph Strauss, it was the first really massive suspension bridge, with a span of 4200ft, and until 1959 ranked as the world's longest. It connects the city at its northwesterly point on the peninsula to Marin County and Northern California, rendering the hitherto essential ferry crossing redundant, and was designed to withstand winds of up to a hundred miles an hour and to swing as much as 27ft. Handsome on a clear day, the bridge takes on an eerie quality when the thick white fogs pour in and hide it almost completely.

You can either drive or walk across. The drive is the more thrilling of the two options as you race under the bridge's towers, but the half-hour walk across it really gives you time to take in its enormous size and absorb the views of the city behind you and the headlands of Northern California straight ahead. Pause at the midway point and consider the seven or so suicides a month who choose this spot, 260ft up, as their jumping-off spot. Monitors of such events speculate that victims always face the city before they leap. In 1995, when the suicide toll from the bridge had reached almost 1000, police kept the figures quiet to avoid a rush of would-be suicides going for the dubious distinction of being the thousandth person to leap.

Perhaps the best-loved symbol of San Francisco, in 1987 the Golden Gate proved an auspicious place for a sunrise party when crowds gathered to celebrate its fiftieth anniversary. Some quarter of a million people turned up (a third of the city's entire population); the winds were strong and the huge numbers caused the bridge to buckle, but fortunately not to break.

悉尼大桥号称世界第一单孔拱桥，早期悉尼的代表建筑。这座大桥从1857年设计到1932年竣工。建成的悉尼大桥是连接港口南北两岸的重要桥梁。

悉尼大桥和大歌剧院是澳大利亚的标志性建筑，澳大利亚艺术家-吉娜多把这俩个标志性建筑

采用澳宝构成这幅优雅魅力的作品。

悉尼大桥被当地居民称为“衣服架”，1857年，悉尼工程师彼得〃翰德逊绘成了第一张设计图，由1400名工人花了8年时间才建好的，耗资达1350万澳元(约合690万美元)。这座桥由大约600万颗铆钉固定，桥拱的跨度为503米，最高处距离海面134米。1932年3月19日，新南威尔士州当时的总理杰克〃兰为该桥举行了正式的开通仪式。

建成的悉尼大桥长502.9公尺，宽48.8公尺，有8个车道，2条铁轨，1条自行车道及1

条人行道。

悉尼大桥有许多重要的意义，它是连接港口南北两岸的重要桥梁、是悉尼歌剧院明信片的完美背景、也是摄取港口全景的绝佳地点。

The Sydney Harbour Bridge is the main crossing of Sydney Harbour carrying vehicular, rail, and pedestrian traffic between the Sydney central business district (CBD) and the North Shore. The dramatic water vista of the bridge together with the nearby Sydney Opera House is an iconic image of both Sydney and Australia. The bridge is colloquially referred to as the Coathanger because of its arch-based design, although this usage is less prevalent than it once was. The iconic Bridge is celebrating its 75th anniversary in 2007.

The bridge was the city's tallest structure until 1967. According to Guinness World Records, it is the widest long-span bridge in the world and is the largest steel arch bridge with the top of the bridge standing 134 metres above the harbour.

The bridge's two ends are located at Dawes Point (in Sydney's Rocks area) and Milsons Point (in Sydney's lower North Shore area). It carries six lanes of road traffic on its main roadway, two lanes of road traffic (formerly two tram tracks) and a footpath on its eastern side, and two railway tracks and a bicycle path along its western side. The western side being 305mm larger that the east side.

The road across the bridge is known as the Bradfield Highway and is about 2.4 km (1.5 miles) long, making it one of the shortest highways in Australia. (The shortest, also called the Bradfield Highway, is found on the Story Bridge in Brisbane). At 48.8 m (151.3 feet) wide, it is the widest long-span bridge in the world (Guinness World Records, 2004). The bridge deck portion of the highway is 1.15 km (0.71 miles) long. It is concrete and lies on trimmers (beams that run along the length of the bridge). The trimmers themselves rest on steel beams that run along the width of the bridge. The trimmers and beams are visible to boats that pass underneath the bridge.

The arch is composed of two 28-panel arch trusses. Their heights vary from 18 m (55.8 feet) at the center of the arch to 57 m (176.7 feet) (beside the pylons).

The arch span is 509 m (1,559 feet) and the weight of the steel arch is 39,000 tons. The arch's summit is 134 m (415.4 feet) above mean sea level, though it can increase by as much as 180 mm (7 in) on hot days as the result of steel expanding in heat. Two large metal hinges at the base of the bridge accommodate these expansions and contractions and thereby prevent the arch from being damaged. The steel used for the bridge was largely imported. About 79%