Last month, we honored the newly-opened, 134-mile-long John Muir Way with a few suggestions for other long-distance walking routes in Scotland. If that's whetted your appetite for more challenging hikes, here are a five trails to start prepping for, from California's epic Pacific Crest Trail to a simple four-day trek in New Zealand. 

Pacific Crest Trail, USA

Made (more) famous by Cheryl Strayed's memoir Wild, the PCT runs all the way from the Mexican to the Canadian border. That's around 2,650 miles in total, passing through seven national parks, including Yosemite, and 25 national forests, including Mount Hood. Hiking the entire trail usually takes four to six months, but the record holder (Josh Garrett) did it in 59 days and 8 hours - averaging close to 45 miles a day.

Milford Track, New Zealand

Far more manageable, but no less spectacular, is the 33-mile Milford Track on New Zealand's South Island. Hiking the length of the track, from the northern shores of Lake Te Anau to Sandfly Point near Milford Sound takes four days; traverses alpine valleys, fjords, and rivers, and takes you to New Zealand's tallest waterfall, Sutherland Falls.

Great Himalaya Trail, Nepal

To complete the entire 1,056-mile-long Great Himalaya Trail, which runs from Kanchenjunga to Humla and passes some of the world's highest peaks and most remote communities, you will need to set aside 160 days. If you can't spare that length of time, however, you can stick to one of the 10 designated sections, some of which take as little as eight days to complete.

Cotswold Way, England

The Cotswolds, in south central England, are a designated Area of Outstanding Natural Beauty. Perhaps the best way to take in the area's small villages, built with local limestone; beech woods, wildflowers, and the picturesque Severn Valley is by walking the 102-mile-long Cotswold Way. As well as a footpath, the Cotswold Way is run each summer as a 10-stage relay race; the record stands at 20 hours and 36 minutes.

Haute Route, France/Switzerland 

Passing through both the Swiss and French Alps, the Haute Route takes around 12 days to walk from Chamonix, France (home of Mont Blanc) past glaciers and snow-capped peaks to the beautiful alpine village of Zermatt in Switzerland. The route can only be traversed in summer, but is suitable for most levels of hikers. Plenty of mountain huts, inns, and hotels line the well-marked route.