Last Wednesday Flamengo of Brazil climbed 3, 800 metres into the Andes to face Bolivia's Real Potosi.

BBC: Tim Vickery column

Potosi draws tourists from nearby Chile and Argentina and now, increasingly, from Europe and North America.

ECONOMIST: Under the ocean, up in the clouds

Indeed, The Strongest and Real Potosi have lost all of their away matches.

BBC: Tim Vickery column

Still, Potosi benefits, or at least those of its citizens who run or work in these and other tours.

ECONOMIST: Under the ocean, up in the clouds

Ghost-like mounds of powder-like gold can be seen, forever waiting for transportation to the northern Mexican city of San Luis Potosi for refinement.

BBC: In Oaxaca, a community unchanged

Together, Bolivar, The Strongest and Real Potosi have played 40 home games, recording 25 wins, nine draws and six defeats, scoring 78 and conceding 41.

BBC: Tim Vickery column

Friday's warning also specifies dangers and advises against nonessential travel in parts of the states of Durango, Chihuahua, Coahuila, Jalisco, San Luis Potosi, Sinaloa, Sonora and Zacatecas.

CNN: U.S. broadens Mexico travel warning

Another girl of 14 years from Potosi was sent by her mother to La Paz to work as a nanny, but ended up doing all the household chores.

BBC: Bolivia sees rise in people-smuggling

Earlier in 2007, Brazilian club Flamengo said they would not play again at altitude after several of their players needed oxygen during a game against Bolivian team Real Potosi, held at nearly 4, 000m (13, 120ft).

BBC: Fifa bans high-altitude football

This is only Potosi's second Libertadores campaign.

BBC: Tim Vickery column