The McMurdo Dry Valleys in Antarctica make up the driest place on the planet. It hasn't rained there in over 2 million years. Polar deserts are different than most of the world's deserts, so the world's true driest desert is the Atacama Desert, in the north of Chile. It’s said to be the driest place on earth, with spots where it hasn't rained for 400 years.
Acid rain refers to rain that has become acidic due to atmospheric pollutants like sulfur dioxide and nitrogen oxides. These pollutants come from man-made sources such as coal power plants, vehicles, and industrial activity. Acid rain primarily impacts aquatic ecosystems, forests, and buildings. As the acidity of lakes and streams increases, it limits the survival of fish and other aquatic plants and animals. In forests, acid rain strips nutrients from the soil and damages leaves. Man-made structures like buildings and monuments also suffer damage as the acidic water chemically wears away stone and metal.
One of the most important “loops” in the water cycle involves evaporation of water from the ocean surface, transport in the form of water vapor to the continents by winds, and precipitation as rain or snow on the continents. The rainfall then runs off by way of streams, rivers, and groundwater back to the ocean.