A cave is a natural opening in the ground extending beyond the zone of light and large enough to permit the entry of man. Occurring in a wide variety of rock types and caused by widely differing geological processes, caves range in size from single small rooms to interconnecting passages many miles long.
Cuban passport. Cuban passports are issued to citizens of Cuba to facilitate international travel. They are valid for 6 years from the date of issuance, but have to be extended every 2 years. The cost of this passport is about US$500 (CUC 500) for every two years if one person lives in the United States. Until January 14, 2013, the Cuban government required that all Cuban citizens and foreigners such as foreign students that live in Cuba desiring to leave the country would have to obtain an exit permit (Spanish: Permiso de Salida).
If you are from Canada, your Tourist Card allows you to stay in Cuba for 90 days. Similarly, if you want to stay in Cuba for more than 90 days, you can extend your Tourist Card for an additional 90 days, at a cost of 25 CUC. The maximum length of stay in Cuba with a Tourist Card for Canadians is 180 days.