The Ardennes Monster Origin is the flagship distance of the Belgian ultra series — a 1,050-kilometre road event from Namur with 20,000 metres of climbing through the forests and river valleys of the Ardennes. Namur sits at the confluence of the Meuse and Sambre rivers and serves as the gateway to the Ardennes plateau, the forested highland region that covers much of southern Belgium, Luxembourg, and parts of Germany and France. The route loops through this territory on roads characterised by continuous short climbs and descents — the Ardennes landscape is one of the most deceptive in European cycling, appearing modest in gradient but accumulating enormous elevation totals through sheer relentlessness. The 20,000 metres of climbing in 1,050 kilometres is comparable to major alpine ultras despite the maximum elevation rarely exceeding 700 metres. The event runs in July, when the Ardennes forests are in full summer green and the days are long. The name captures both the character of the terrain and the attitude required to complete it. Riders who underestimate the Ardennes because of its modest altitudes consistently report it as harder than expected — the Monster is an apt description.
Estimate your finish time for The Ardennes Monster – Origin (1050km) based on your target pace.
Learn how to prepare for The Ardennes Monster – Origin (1050km), from pacing to nutrition.
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Based on this event's terrain, difficulty and riding style.
At 1050 km with 20000 m of elevation gain, The Ardennes Monster – Origin (1050km) is roughly the distance of 25 marathons back to back, with climbing that adds up to more than 2.3 times the height of Mount Everest.
A Endurance Road Bike is the right tool for The Ardennes Monster – Origin (1050km). Set it up with 30-35mm Tubeless rubber and gear it low — a 46/30T-50/34T (2x) chainring and 10-36T cassette will keep you spinning on the steeper sections.
The Ardennes Monster – Origin (1050km) carries an overall difficulty rating of Advanced. The terrain itself is mostly smooth, fast-rolling surfaces, the climbing is consistently demanding, with sustained climbing, and conditions tend to run mild and generally comfortable.
The Ardennes Monster – Origin (1050km) takes place on May 5, 2026. That puts it in spring, when weather can still be unpredictable, so a flexible kit is worth packing.
The Ardennes Monster – Origin (1050km) runs primarily on road, and we'd recommend 30-35mm Tubeless tires to handle it comfortably.