This remark­able and remote tun­nel in Cal­i­for­ni­a’s Mojave Desert was the work of a sin­gle and very deter­mined man. Gold min­er William “Bur­ro” H. Schmidt began bur­row­ing out the pas­sage in 1902 start­ing from his cab­in (which is still there) and going through Cop­per Moun­tain in the El Paso range. It leads onto a pre­car­i­ous ledge 4,000 feet (1,219m) up. It took him almost 40 years to man­u­al­ly dig the tun­nel, with just the odd stick of dyna­mite to help blast through the sol­id rock. What makes the tun­nel all the more intrigu­ing is that nobody is entire­ly sure why he dug it.