Part of the Golden Circle tour, the artist Bjork held a concert at this volcanic crater because of the great acoustics. It is starting to gain acceptance that the crater was formed from a volcano which emptied all its magma reserves and caved in rather than a volcanic explosion. When you return to Reykjavik sightseeing make sure to try great Iceland food such as fish and chips (hot dogs are very common as well).
Check our Top 5 section for more Iceland sightseeing activities! And dont forget to ask your tour operator for more things to do in Iceland as well.