Reykjavik for The Thrill Seekers: a Friday-to-Monday weekend

Nine kilometres on the shoreline path past Skerjafjörður to the geothermal beach; it is flat, lit and busy in every season, and the beach hot pots are the cool-down.

The 1937 pool hall has outdoor hot pots at 38 to 42 degrees and a cold tub at 8; open late on weekdays, and a very local way to recover.

The harbour burger joint: a plain, fast, properly good cheeseburger with a pile of chips, which is tonight's recovery plan and tomorrow's fuel in one paper bag.

Two hours in a drysuit in 2 to 4 degree glacial water between the North American and Eurasian plates, with visibility past 100 metres; operators set a minimum age of twelve.

Walk the rift wall to the waterfall in the old parliament valley, warm and dry again; parking at the visitor centre is paid, and winter paths can be icy.

Fish served bubbling in cast-iron pans, arctic char or cod with potatoes and butter; a big, cheap-for-Reykjavik refuel and the room is loud and friendly.

A 3.5 km climb each way past steaming vents to a warm river you can bathe in; changing is on open boards in the wind, and ice makes winter harder than it looks.

A lava tube over a kilometre long, about 5,000 years old, walked on a guided tour with a helmet and headlamp; wear boots, because it stays around freezing inside all year.

A converted bus station of food stalls: lamb soup, ramen, fish and chips and a bar, so the whole group eats exactly what its legs ask for.

A twenty-minute drive north, then a steep 6 km round trip to the Steinn rock at 597 metres; rocky and exposed at the end, and in winter only with crampons.

The city's biggest pool, with outdoor lanes and hot pots from 38 to 42 degrees; shower without swimwear first, which the attendants do enforce, then soak the legs.

The harbour hot dog stand open since 1937: order one with everything, which means raw and fried onion, ketchup, sweet mustard and remoulade, eaten standing up.