Used for water distribution, the Delaware Aqueduct in New York, USA is the longest tunnel in the world (as of 2010). Drilled through solid rock, it reaches a staggering 137 kilometres (85 miles) in length. More tunnel facts.

Construction on the Leaning Tower of Pisa began on August 9th, 1173.

An electric eel can produce a shock of up to 650 volts.

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