Runners conquer obstacles at UK's Tough Mudder challenge
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Runners battled obstacles and swam across mud pools to take part in the annual Tough Mudder challenge at Belvoir Castle in the UK on May 18, 2019. /VCG Photo

Runners battled obstacles and swam across mud pools to take part in the annual Tough Mudder challenge at Belvoir Castle in the UK on May 18, 2019. /VCG Photo