The Virgin, the Monk, and the Ogre - in German, the Jungfrau, the Moench and the Eiger - are three classic Swiss mountains that for centuries have drawn artists, thrill-seekers and tourists.
For a weekend tripper, the big lure is the railway to Europe's highest railway station at Jungfraujoch (3,454 metres above sea level), which in 2012 celebrated its centenary. It means that even the unfit can make it through walls of rock and ice to extreme mountain terrain and year-round snow with the status of a UNESCO World Heritage Site.
You won't resent the nearly 200 Swiss francs fare for a standard class return - provided the weather is clear.
Upfront investment in a rail pass gives free travel on some routes and discounts on others, including on the section to the Jungfraujoch. It's worth it if you're a dedicated train traveller, willing to stretch your weekend and travel by rail all the way.
From Paris, it's a roughly five-hour rail journey to Bern and then just under an hour's connection to Interlaken, recommended as a base for your stay.
From London, you have to add on the Eurostar journey to Paris (just over two hours). Otherwise, the nearest airports are Bern and Zurich.
Accommodation includes the five-star Victoria-Jungfrau, formerly frequented by the likes of the writer Mark Twain and the Emperor of Brazil. With equally good views - of the Jungfrau, Moench and Eiger - at a fraction of the price, Lazy Rancho, a bus-ride away from Interlaken town, offers five-star camping - if you've packed your light-weight tent.
Reuters correspondents with local knowledge suggests how visitors can get the most out of a 48-hour visit.
Interlaken is little more than one main street - the Hoeheweg - which runs between the East and West Stations.
It's worth a couple of hours browsing, with the caveat that if this looks set to be your clearest day, head straight for Jungfraujoch and save your the "Day One" programme for Day Two.
Once you're sated with tourist shops selling Swiss Army penknives and miniature cow bells, pause for a high quality hot chocolate at Das Grand Cafe Restaurant Schuh on the edge of the Hoehematte - a park, where you can watch paragliders come in to land against the backdrop of the Jungfrau.
11:00 a.m. - Time to take the train to Grindelwald from Interlaken Ost (East) (just over half an hour).
One of Grindelwald's claims to fame is its appearance in the James Bond film "On Her Majesty's Secret Service", which includes a chase through a Christmas festival in the town.
It also has clear views of the North Face of the Eiger and carries keen memories of its many tragedies.
British writer and climber Joe Simpson, amongst others, has narrated the story of the tragic 1936 expedition, whose achievement was to unlock the secret of traversing the North Face.
Sadly, none of the climbers survived the attempt. The last survivor managed to recount his tale as he dangled, freezing slowly to death on the end of a rope, just out of reach of the rescue team.
On a sunny afternoon out of ski season between spring and early autumn, such tragedy seems remote. Walk through Grindelwald from the train station, past more tourist shops, to take the cable car to First.
1:30 p.m. - After a drink and a sandwich at the restaurant at the top, looking down the valley, choose from a range of walks, clearly labelled according to difficulty and length.
Grindelwald is remarkable because in theory the glaciers reach very deeply into the valleys and the First vantage point gives views of them. It also shows the extent of their retreat. A signpost near one of the footpaths tells you the glacier would have been at your feet only a century ago. You now have to strain to see it.
Melting glaciers are a major threat as huge chunks of rock have crashed down into the valleys. Once it was the glaciers themselves that were feared. Centuries ago, Swiss mountain dwellers prayed they would disappear. Now they pray for the opposite and the Pope has given his blessing.
5 p.m. - After a few hours of taking in the scenery, with and without glaciers, time to head back down the cable car.
You could opt for dinner in Grindelwald before taking a late train to Interlaken. Options include Onkel Toms Huette, renowned for pizzas, particularly good after all the fresh air.
Alternatively, take an earlier train back down to Interlaken in time for dinner there. The Steinbock steakhouse by the river gets rave reviews.
8:30 a.m. - After a hearty breakfast of Bircher muesli, head for Jungfraujoch.
From Interlaken Ost, a train just after 9 a.m. will get you to the top for around 11:30.
There are two routes to choose from - via Grindelwald or via Lauterbrunnen and Wengen. Ascending via Grindelwald leaves you the option of travelling down via Lauterbrunnen for a change of idyllic scenery.
For much of the route, you're on a cog wheel railway, which after a change of train at Kleine Scheidegg, hauls you through a series of tunnels. A viewing platform allows you to look out on the North Face. Expert climbers can get out and climb it.
The section from Kleine Scheidegg lasts around 50 minutes and is complete with tourist commentary.
In-your-face tourist content continues on arrival, when activities on offer include touring an ice palace, ski lessons, dog-sled rides, and an observation post named the Sphinx terrace, with stunning views.
The viewing terrace is part of a high altitude research centre (not open to the public), which anxiously monitors the retreating glaciers.
If the weather is changeable and you're exhausted by the altitude, you could dine at one of the restaurants near the railway station. The more adventurous option is to follow the signposts for a roughly one and a half hour walk through the snow to the Moenchsjoch hut.
At an altitude of 3,658 metres, it is one of the highest huts owned by the Swiss Alpine Club and you'll almost certainly see climbers arriving to stay the night or leaving for an expedition.
You can content yourself with just watching from the restaurant with yet more breath-taking views.
Around 4 p.m. - Time to descend. If you take the Lauterbrunnen route down, you could stop for a wander and dinner in Wengen, one of Switzerland's few car-free villages, famous in winter for high-speed down-hill skiing.
Many of the restaurants are in hotels and many offer traditional Swiss roesti, guaranteed to fill you up.
Trains run until around 10 p.m. to whisk you back to Interlaken before an early train or plane back home.