Backblip: Strokkur, Kerið Crater, Gullfoss, Aurora

Yet another amazing day in Iceland! The highlight for me was the Strokkur geyser and its surroundings in the late afternoon light so the main blip and 3 extras were taken there  (do you see a dog shape in the eruption in the first extra?). However earlier in the day we'd explored the Kerið Crater (4th extra) and we also visited Gullfoss waterfall (5th extra).

As if that wasn't enough our leaders hoped to find us another aurora, so at about 10.30pm we set off for another half hour drive to a location we'd scouted out in the morning - and we had another excellent show (the final extra)! It's just as well we were well wrapped up as we finally set off back to the chalets at about 1.30 am and it was definitely chilly!

Strokkur geyser is in the Haukadalur valley, a very active geothermal area. It seems that it first erupted in the late 18th Century after an earthquake but round about 1900 it stopped. Locals cleaned out its conduit in the early 1960s and it's been erupting about every 10 minutes or so since then. Very close to it is Geysir (from which our generic word "geyser" originates) but it's almost totally dormant these days.

Kerið Crater is a "mere" 6,500 years old – making it one of the three most recognizable volcanic craters in Iceland. The caldera is approximately 55 m deep, 170 m wide, and 270 m across, and is made up of a unique red volcanic rock. You can get an idea of its scale by the tiny people you can see descending into it - and some on the rim too.