In Quaternary science and other branches of Earth sciences, proxy data provide indirect information on the climate or environmental conditions of the past (Walker 2005; Mauri et al. 2015). Because scientists do not have the chance to directly measure or observe the properties of past climates or environmental changes (for example, wildfires or soil erosion) in detail, other sources of data need to be explored and combined in support of any reconstruction and final conclusions. Proxy indicators are interpreted in light of our knowledge of the present conditions and their impact on the biosphere, pedosphere, and landscape dynamics. These indicators are also compared with other proxy data to identify notable similarities or striking differences. A valuable source of information is determining places where various types of materials could have been deposited and kept intact. This means that the deposits formed a set of layers that were not disturbed during or after deposition, did not contain gaps (hiatuses), and were not physically or chemically contaminated during or after deposition. The most favorable conditions for this type of continuous deposition are in ocean and sea basins, at lake bottoms, and in ice bodies (glaciers, ice fields, and ice caps). Other natural data archives include tree rings and karst features (for example, stalactites and stalagmites). These features are potential sources of highly valuable information on past climate and environmental conditions. This information is obviously incomplete and indirect, but at the same time, it is unique and often the only data we have available (Fig. 4.1).