Rubber was a common resource for the Indians of Central and South America since well before Columbus landed in the New World. This naturally occurring rubber allowed waterproofed shoes, playing balls, and other pragmatic benefits, but had the problem of shortly losing its elasticity. The process of vulcanizing, discovered accidentally by Charles Goodyear in 1839, improved not only its elasticity but also its ability to stay pliable in hot or cold weather. The first synthetic rubbers began appearing towards the end of the 19th century in Europe. Though they were of limited benefit (because of inferior quality compared to natural rubber) one advantage was independence from having to import the material from regional plantations. The Germans learned this lesson well during World War I, when the British Navy shut down many of their naval shipping routes.