More than 300 cyclists have signed up for a 24-hour mountain bike endurance race to be held near Fort William.
Half the mountain bike event will take place in darkness
The weekend's Relentless 24 has drawn entries from across the UK.
The event will be staged on the Witch's Trail and recently constructed world championships courses in Leanachan Forest and the Nevis Range.
The route will start and finish at the Nevis Range complex, after a climb up Aonach Mor and into forest. It will start at 1200 BST on Saturday.
Half of the event will take place in the dark.