Natural silence -- the kind when you hear nothing but the sound of nature around you -- is becoming increasingly scarce. The rumblings of man-made noise can be heard even in the remote corners of national parks and deep in the Arctic Ocean.
원문출처 : https://www.cnn.com/travel/article/quiet-parks-quiet-places-noisy-planet-spc-intl/index.html
원문출처 : https://www.cnn.com/travel/article/quiet-parks-quiet-places-noisy-planet-spc-intl/index.html