How sinkholes are formed - in 60 seconds

Name: How sinkholes are formed - in 60 seconds
Uploaded: 2015-10-02T13:55:15.000Z
Duration: 57 s
Description: More sinkholes have been seen across the UK in recent years, large gaping holes suddenly appearing in the ground.

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Sinkholes, like the one which developed in St Albans on Thursday, are large gaping holes which suddenly appear in the ground.

They are often caused by an abnormal amount of water seeping into the ground, but they are difficult to predict.

BBC News has a look at what causes sinkholes to open.

2 October 2015