Located on the seismic zone that rings the Pacific Ocean, Taiwan abounds with volcanic topography and geothermal energy. These are necessary for sulfur springs. What’s more, the metamorphic and sedimentary rock on the either side of the Central Mountain Range are full of minerals which react with hydrogen carbonate ions, which is necessary for carbonated springs. All told, there are over 100 hot springs of various kinds around the island. There are also very few cold springs. But Taiwan is endowed with hot springs, cold springs, murky hot springs, and seabed hot springs. In response to the government’s call to publicize the beauty of Taiwan’s hot springs so as to encourage citizens to take vacations, promote tourism and stimulate the economy, Chunghwa Post has chosen four different types of springs in four famous scenic locations as a set of four stamps on hot springs in Taiwan. The stamps feature the Yangmingshan Hot Springs, the Suao Cold Springs, the Guanziling Murky Hot Springs and the Green Island Seabed Hot Springs. On the upper left corner of each stamp is a teardrop-shaped window with the picture of a local landmark or vista. The main designs of the stamps feature images of people soaking in the springs, thus showing the pleasure involved. In the lower left corner of each stamp is a symbol that denotes hot springs. Descriptions of the stamps follow:(1) Yangmingshan Hot Springs (NT$5): Most hot springs here are sulfur springs, with a temperature ranging between 60° to 70°C. This water is for bathing only. Approach Yangmingshan through Yangde Boulevard and then take the Yang-Jin Highway. Along the highway, many signs indicate previous volcanic activity. The landscapes of Siaoyoukeng and Sulfur Valley fumaroles are the spots that are well worth a stop. A picture of these fumaroles is found in the teardrop-shaped window on the upper left corner of the stamp.(2) Suao Cold Springs (NT$5): It rains a lot in the Suao area, and rainwater percolates down into the earth’s crust to a depth of about 2,000 meters, reaching cracks in the slate. Then, as a result of tectonic movement, the carbonate content in the rocks dissolves and releases a large amount of carbon dioxide, making the underground water bubbly and pushing it to the surface in the form of carbonated cold springs. The springs here are used for drinking as well as bathing. The temperature of the water is about 22°C. The design of the stamp includes Cold Springs Park and Nanfangao Bridge.(3) Guanziling Murky Hot Springs (NT$10): The rising spring water here brings minerals, salt and mud particles with them when it goes through the mudstone layers below the surface, making the spring water look murky and even black. Therefore, it is also known in Chinese as the Black Hot Spring. This is an alkaline carbonate spring, of a temperature about 75°C. This water is for bathing only. Featured in the teardrop-shaped window on the upper left corner of the stamp is a photo of the famous ShueiHuoTongYuan (which means “where water and fire spring from the same source”). The reason for this spectacular phenomenon is that spring water and natural gas are both coming out of the cliff surface at Mt. Jhentou, so that when the gas is lit, you get water and fire together.(4) Green Island Seabed Hot Springs (NT$25): The hot springs here rise out of groups of rocks and reefs along the shore. The temperature of these acidic sulfur springs ranges between 53° to 93°C. The water has a high salt content and is undrinkable. The teardrop-shaped window in the upper left corner features the island’s most famous landmark: the Green Island Lighthouse.