trail centres. Off-road trails often incorporate a mix of challenging terrain, singletrack, smooth fireroads, and even paved paths. Trails with an easy or moderate technical complexity are generally deemed cross-country trails, while trails difficult even to experienced riders are more often dubbed all-mountain, freeride, or downhill. Downhilling is particularly popular at ski resorts such as Mammoth Mountain in California, USA or Whistler Blackcomb in British Columbia, Canada, where ski lifts are used to get bikes and riders to the top of the mountain. Long rides on hiking and mountain paths have some resemblance to cycle touring but the latter usually take place on tarmac. However, mixed terrain cycle-touring, nicknamed "rough riding" in Canada and the US and "rough stuff" in Europe, is a form of trail riding, because it involves cycling over a variety of surfaces and topography, on a single route, either using a mountain bike or hybrid bike. A new style of travel called adventure cycle-touring or expedition touring involves exploring remote regions of the world on sturdy bicycles carrying lightweight gear. This type of trail riding is in fact a form of backpacking. Mount Tamalpais, California, USA, and the surrounding areas in Marin County, California are recognized as the birthplace of mountain biking. In the 1970s, mountain biking pioneers such as Gary Fisher, Otis Guy, Charlie Kelly and Joe Breeze were active. The 2006 film Klunkers chronicled their story, solidifying Mount Tamalpais' legendary status as a trail riding destination. There has been considerable controversy around trail access for mountain bikes, both in terms of environmental impact and the safety of other trail users. As a result, bicycles are generally restricted from narrow, single-track trails, though bicycles are allowed on most fire roads. However, mountain bikers in the United States generally have access to multi-use trails. In England and Wales, bridle paths and some other rights of way, such as byways and 'Roads used as paths' (RUPP), are open to cyclists, but footpaths are not. However, in Scotland there is no legal distinction between footpaths and bridleways, and it is generally accepted that cyclists and horseriders may follow rights of way with suitable surfaces. Rights of way are somewhat limited in Northern Ireland. There are long-distance routes throughout Europe, including some through the Swiss Alps that involve crossing high Alpine passes. There are also extensive routes through France that include both steep, rocky, alpine terrain and minor country