1. El Yeso Dam, also known as Embalse El Yeso, is a large reservoir located in the Andes Mountains near Santiago, Chile. It was constructed in 1964 and has a capacity of 250 million cubic meters of water. The dam is approximately 215 meters in height and has a length of 350 meters. The reservoir is used for hydroelectric power generation, irrigation, and drinking water supply for the city of Santiago. The beautiful turquoise color of the water is due to the glacial minerals present in the Andes Mountains.

2. El Yeso Dam is open to visitors from October to May, but the exact working hours may vary depending on the season and weather conditions. It is recommended to contact the tourism office or a travel agency for the latest information. Unfortunately, we do not have a phone number at this time.

3. Visitors to El Yeso Dam must obtain a permit from the forestry service (CONAF) in advance. The permit can be obtained online or in-person at a CONAF office. Additionally, visitors must hire a certified guide to enter the dam area. Travel agencies and tour operators can also arrange for permits and guides. As for transportation, visitors can either drive (a 4x4 vehicle is recommended) or take a guided tour from Santiago.