Quadzilla consists of four marathons on four consecutive days in early February at Caldecotte Lake, Milton Keynes. The start/finish area is Lakeside Grove, conveniently located near the A5 and a short drive from the M1. Each day features a full marathon with a strict seven-hour time limit; participants exceeding this limit are marked as DNF.
The course is straightforward yet demanding: each marathon involves 7.5 laps around Caldecotte Lake. The first two runs proceed clockwise, with the subsequent two going anti-clockwise, offering a different perspective of the lake for fatigued participants. Runners receive a route description at registration, attend a mandatory briefing ten minutes before each start, and encounter aid stations on every lap. Completing each marathon earns a unique medal, and those registered for all four receive a finisher's hoody. The event adheres to 100 Marathon Club rules, catering to its participants: individuals tracking marathon totals, multi-day runners, and those seeking a four-day challenge.