At the start of the year I spent 10 days on Lanzarote in the Canary Islands.? The whole island has been created by volcanic activity and I was fascinated by its many different geological features such as the Jameos del Agua and La Cueva de los Verdes.
I also visited one volcano where you can walk into the crater created by an eruption. I climbed up the outside and looked down into it before I realised that you could just walk in at one point where there was a gap in the crater wall.
View of crater from above