Going inside volcano Thrihnukagigur in Iceland is an extraordinary opportunity (though a bit pricey). A small group of six to eight people board a window washers’ scaffold and are lowered through a narrow rock opening and down about 400 feet. As you are descending, you enter into a huge, colorific, tear-drop-shaped volcanic chamber.
The formations and vibrant colors of the chamber are amazing. You can explore the volcano floor for 20-25 minutes. Meanwhile the scaffold returns to the surface for the next group.
Find out more about this volcano at https://insidethevolcano.com/the-volcano/