Without oxygen, you can say goodbye to the Hoover Dam, the Pantheon Dome and anything else made out of concrete.

没有氧气，你就再也见不到胡佛坝、万神殿圆顶和其他混凝土建筑。

Drones are off-limits in the airspace in the 15-mile radius around Washington and also over places like the Hoover Dam, the Statue of Liberty and Mount Rushmore.

距离华盛顿方圆15英里的空域都是无人机禁飞区，胡佛大坝、自由女神像和拉什莫尔山也是如此。