By Hannah Richardson
BBC News education reporter
The pupils were on a geography field trip in Iceland
When 40 school pupils went to Iceland to study geothermal activity they had no idea quite how close to the action they would get.
Their six day tour of the country ended up being the geography field trip to end all field trips.
Not only did the pupils, from Presdales and Richard Hale schools in Hertfordshire, stand on the glacier covering the volcano, they actually saw it erupting.
Geography teacher at Presdales School in Ware, Lucy Smith, said: "We were standing on a beach looking at coastal geography 10 kilometres away when it was erupting.
"Because it is under the ice, we could see these huge columns of steam about four kilometres high."
Vicky Spencer, head of geography at Presdales said: "Although it was fairly exciting we were quite remote from it.
"We were certainly in no danger. Iceland is incredibly well set up to deal with these things."
'Wrong way round'
The group had planned to come back from the coastal town of Vik, where they had been staying, to catch a flight just outside Reykjavik when they heard the road had closed.
Miss Spencer said: "There is only one main road going round Iceland and they had dug it up to let the flood water caused by the eruption out.
"So we had no choice but to go the other way round the island."
So the school party embarked on an 18-hour coach trip the wrong way around the whole of Iceland to get the country's international airport at Keflavik.
Miss Spencer said: "We ended up taking the long way round - the scenic route if you like.
"And it really was scenic we saw lots on the way, the fjords, reindeer and glacial fields."
The students stood on the glacier covers the exploding volcano
Miss Smith added: "It was a great adventure - the kids were brilliant and they absolutely loved it.
"We had to travel through the night so we said to the children you will have to be good and go to sleep and everything.
"Then we ended up waking them all up to see the Northern Lights - it was just something they would never have seen otherwise."
They then caught one of the last flights out of Iceland to Glasgow, from where it took another nine hours on a coach to get them back to Hertfordshire.
Head teacher Janine Robinson said: "They had an amazing experience as they were able to see other parts of Iceland.
"They arrived back a day late having had a brilliant journey and they were in very good spirits but very tired.
"We had a whole school assembly on Monday morning about their experiences.
"And we gave the geography team a round of applause for their endurance."
She added that one of the school's mottos was about adopting a positive attitude in times of adversity.
"This is exactly what these staff and students showed. They actually got more out of the trip then they would have otherwise have done.
"It just goes to show if things get tough - you just have to get on with it."