Deepest

The world's deepest gorge isn't in the US or Africa, it's in Zagoria, northwest Greece. Height/width ratio is the thing that matters, and the Vikos gorge plummets 900 metres at a point where it is 1,100 metres across, creating a dramatic sheer-sided vault with beech, fig and oak trees encasing the Voidomatis river. The gorge is home to brown bears, wild boar, elegant arched bridges and trails linking spectacular mountain villages.

· Travelux (01580 764344, travelux.co.uk) offers seven nights' B&B fly-drive with maps and self-guided walks from £625pp.

Darkest

Kielder Forest in Northumberland is the location of the country's latest observatory, which opens next February. As well as having England's lowest light pollution - Newcastle, the nearest conurbation, is nearly 50 miles away - it also has our driest weather, with night-time rainfall as low as the Nevada desert. Find out for yourself at October's free Forest Star Camp, where enthusiasts identify constellations and distant star clouds.

· Kielder Forest Star Camp (01226 246351, richarddarn.demon.co.uk/starcamp). Tent pitches £10 a night.

Cleanest

Tucked away on the western rim of Croatia's Dalamatian archipelago, Vis has been named one of the 10 best-preserved islands in the Mediterranean by the World Wildlife Fund. Its clear azure waters contain seagrass meadows, dolphin, rare turtles and sardine. And the locals' rejection of a planned tuna farm suggest the island is standing firm against commercial development.

· Two hours by ferry from Split £3.80 (jadrolinija.hr), four-storey town house from £65 a day (thisisvis.com).

Highest

It must be the clean mountain air, but at 2,126 metres, Juf, the highest settlement in Europe, has been inhabited continuously for nearly 800 years. Just 30 people now live on the steep meadows, sandwiched between Alpine forest and mountain peaks in southeast Switzerland's Averser Valley, where hunters first melted cheese over their lunch in the 13th century. Now its prime location beneath Mt Staller and the Septimer Pass attracts skiers, hikers and mountain bikers.

· Pension Edelweiss (0041 816 671134, pension-edelweiss.ch) has B&B doubles from £38.

Wildest

Swedish Lapland, the nearest thing Europe has to the vast wildernesses of North America, blends lakes, surging rivers and huge glacial valleys - and is accessible to hikers, skiers and wildlife enthusiasts. You can see the northern lights in winter and midnight sun in the summer in between trekking the Kungsleden, one of the world's great hiking trails.

· Swedish Tourist Federation station rooms (svenskaturistforeningen.se) are available for day walks or as part of longer hikes. Abisko, at the start of Kungsleden, costs from £36pp per night.