Sem explicação

From Costa Rica's Great Balls to Death Valley's wandering rocks: The 10 bizarre phenomena that still have scientists baffled

• Great balls of Costa Rica date back to 600AD yet their purpose is unknown
• In Serbia and Japan, frogs and other wildlife are said to fall from the sky
• Stones slide across the ground under a mysterious force in California
• While no one knows how vast shapes appeared in Peruvian sand

Read more: http://www.dailymail.co.uk/sciencetech/article-2528351/From-Costa-Ricas-great-balls-wandering-rocks-Death-Valley-The-10-natural-phenomenon-modern-science-explain.html#ixzz2olsCKXmN
Follow us: @MailOnline on Twitter | DailyMail on Facebook