A sphere with a diameter of 1,385 kilometers would represent the total volume of water on Earth, including oceans, ice caps and glaciers, lakes, rivers, groundwater, and water in the atmosphere, according to the United States Geological Survey (USGS). This volume, which is approximately 1,386,000,000 cubic kilometers, is often illustrated by the USGS Water Resources account on social media, especially on Earth Day. Although water covers 71 percent of Earth's surface, its total volume is relatively small in comparison to the planet's overall size. Of Earth's total water, 96.5 percent is salt water, and only 2.5 percent is fresh water. Of this fresh water, the liquid portion that is accessible to humans forms a sphere with a diameter of just 56.2 kilometers. If glaciers and polar ice caps are excluded, and only fresh liquid water such as groundwater, lakes, rivers, and wetlands are considered, the sphere representing this water would have a diameter of about 272.8 kilometers. If only lakes and rivers are considered, the sphere would shrink further to a diameter of 56.2 kilometers, a size that would fit within a French department. The USGS has emphasized that while water is abundant on Earth, accessible fresh water remains a rare and precious resource. The oceans, which contain more than 96 percent of Earth's water, are described as a "thin film" over the Earth's crust, with an average depth of about 2.7 kilometers, compared to the Earth's radius of more than 6,000 kilometers. This highlights how the volume of water appears minuscule in comparison to the entire planet. At any given moment, approximately 12,900 cubic kilometers of water, mainly in the form of vapor, are present in the atmosphere. If all this vapor were to fall as precipitation at once, it would cover the Earth with only about 2.5 centimeters of water. This serves to relativize the idea of a planet submerged in water, emphasizing that Earth rests on an incredibly thin and concentrated water resource.