请将下面这段话翻译成英文：

　　秦始皇(Emperor Qin Shi Huang)统一各国后，修复、连接并扩展了先前各国修建的城墙，将其建成巨大的军事防御工程，东起辽东半岛(Liaodong Peninsula),西至临洮。这就是举世闻名的万里长城。长城是世界一大奇迹，由数百关隘(pass)、堡垒(fortress)、塔楼和城墙构成。每隔一定距离，就建一个烽火台，敌人接近时，发出警报。位于北京的八达岭长城、慕田峪长城和司马台长城都建于明朝时期。如今，长城每年都吸引着众多国内外游客前来参观。它不仅是艺术非凡的文物古迹，同时也是中华人民伟大力量与智慧的结晶。

　　参考翻译

　　After Emperor Qin Shi Huang united the separate states, he restored, linked up and extended the city walls built by the former states into huge military defensive works which started from the Liaodong Peninsula in the east and ended at Lintao in the west.This is the world-famous Great Wall.It is one of the important wonders of the world,consisting of hundreds of passes，fortresses, towers and walls.Beacon towers are built at certain intervals to give the alarm if enemies approach.The parts of the Great Wall situated at Badaling,Mutianyu and Simatai in Beijing were all constructed during the Ming Dynasty.Nowadays,the Great Wall attracts a great many tourists from home and abroad each year.It is an artistically extraordinary cultural relic and historic site as well as the crystalisation of Chinese people's great strength and wisdom.