Lava tunnel + Svarta Kaffið bread-bowl soup

Raufarhólshellir is a 1,360-metre-long lava tube about forty minutes east of Reykjavík, formed in an eruption five thousand years ago, and one of the longest accessible lava tubes anywhere. A guide hands you a hard hat and a headlamp and walks you through frozen waterfalls, coloured mineral walls, and silence so complete it rings. In winter the ice sculptures inside are absurd; it is worth going for those alone.

It is sixty-eight kilometres round-trip on the Ring Road — easy in a rental, feasible if not especially comfortable on the tour bus.

Drive back into 101 and go straight to Svarta Kaffið on Laugavegur. The restaurant basically serves one thing — soup in a bread bowl, meat or vegetarian, with refills on both — and it is exactly what you want. Two-room upstairs setting above a bar, warm wood, a lot of quiet murmuring in Icelandic.