A great hiking option on Isabela Island is Minas de Azufre. These are sulfur mines that were used in the past, and the walk from the base of Sierra Negra Volcano to get to them is a very lovely one. There are a lot of interesting bird species to view along the way, such as hawks, paradise fly catchers and martins. For those that like to be active, this is commonly rated one of the top things to do in Isabela Island.