* Astronomy

Looming over the city, the mountain has been exploited ever since silver was first discovered in 1545, but after almost five centuries it is showing warning signs of exhaustion.
Its peak has lost its once perfect cone-like shape. In January a huge crater formed at the top, and geologists are worried that the mountain may be at risk of collapse.
Hilarion Andrade of Comibol, the government's mining authority, said the crater - which measures 350 sq m in area and 20m in depth - proved the fragility of the mountain. He blamed the crater's formation on the uninterrupted exploitation of the past.
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