As the train pulls into Brig, in canton Valais, I check in my backpack to make sure I have brought water and a warm sweater. It is a baking hot day, but I will need both on my trip to see the largest glacier in the Alps - the Aletsch.
People stream out of the station and I follow the flow to another train that will take me on a 30-minute journey to the town of Mörel. From there, I board a cable car. There is just one working at the moment, but in winter I would have a choice of seven in the whole area.
The tourist office proudly promotes the seven additional chair lifts and 18 ski lifts, which can cope with up to 30,000 people an hour in the peak season. It is clear from the infrastructure that the local economy is heavily reliant on mass tourism, and it has accommodation for more than 1.6 million overnight stays a year.
As the cable car swings into its final stop of Riederalp I ready myself for the half-hour walk to the 2,100- metre peak, which will actually allow me to look down on the Aletsch glacier.
I make my way slowly up to the Villa Cassel, which was built at the beginning of the 20th century by the English banker, Sir Ernest Cassel, as his summer retreat. It is now run by the Swiss environmental group, Pro Natura, and lies at the heart of what has become a protected area.
Tourism has been allowed to develop in the surrounding towns of Belalp, Bettmeralp and Fiesch, but here, just above Riederalp, Pro Natura is trying to preserve a very special part of the Alps. The trails leading to the glacier are clearly marked, and there is a strict "look but do not touch" policy. The Villa Cassel - or the Pro Natura centre - lays on seminars and guided tours to show the effects of global warming on the glacier.
Laudo Albrecht, the manager of the centre, says those effects would be compounded if tourism were allowed to take over the whole area. The cantonal authorities are pushing for the Swiss government to give its support to the campaign to have the Aletsch internationally recognised as a protected site.
"In 1933 the forest of Aletsch on the edge of the glacier became a protected area," says Albrecht. "That was the 'bronze medal'. In 1984 the 'silver medal' was awarded when the Aletsch received national protection. If the area were to become a Unesco world heritage site, that would be the 'gold medal' giving the glacier the highest possible protection in the world."
The Aletsch glacier stretches from the Jungfraujoch in canton Berne to Riederalp in canton Valais. Along those 24 kilometres, it drops in altitude from 4,000 metres to just 1,500. That makes it not only the longest glacier in the Alps, but also the one with the biggest difference in altitude.
It is a unique landmark, which Sirikit Bhagwanani from the environmental group, Mountain Wilderness, says is one of the criteria a site has to meet before it can be added to the Unesco list. If the Aletsch were to be included, it would be the first natural wilderness site in Switzerland on the list.
But Bhagwanani says there is a risk of just a few natural sites in Switzerland achieving international protected status. "By putting a label on certain sites, we are likely to forget about the others" she says. "If one place does not have any label, this does not mean it is not worth being protected."
The walk through the Pro Natura centre to the Aletsch takes me through the forest on the edge of the glacier. It is home to a host of wild animals, and it is also one of the few places where the arve tree, a needle pine tree, can still be found.
As the glacier retreats, it makes more land available for the forest, as it has been doing for the last 300 years. But global warming has recently increased that pace of retreat to 50 metres a year. Albrecht says the forest cannot cover the area at the same speed, and as I look down, I can already see a barren patch developing.
Up to 70,000 people visit the protected area every year. Albrecht would like to see that figure increase. He says the centre's work is important because it shows visitors what is being protected, and makes them more sensitive to the effects of global warming.
The infrastructure already exists to cope with winter tourism, but is underused in the summer. Albrecht is confident that his team could manage an increase in visitors without posing a threat to the environment.
Tourism would not endanger Switzerland's wilderness areas if it were well managed. Bhagwanani says the threat comes when tourism spreads to new areas and is not concentrated in specific places.
She is critical of new trends, such as helitourism, which give skiers access to remote areas. Up to five people are taken by helicopter to summits, which have no ski lifts. Bhagwanani says these skiers destroy the ecological balance of the area and disturb the wildlife.
"We have enough bad examples of the impact of tourism. We have to preserve these remote areas and the last zones of wilderness instead of exploiting everything that can be sold."
As I look down at the Aletsch, it is clear that environmentalists such as Albrecht and Bhagwanani still have time to make their case for more protection for the area. But that time is slowly melting away.
by Jonathan Summerton