OPTIONAL EXTENDED ROUTE: 100-hour ultra marathon combining Athens-Sparta-Athens (485.3km) with continuation to Marathon (39.6km). See main event: 10th Authentic Phidippides Run 2026 - Athens - Sparta - Athens 485km. NOT a separate race - this is an EXTENSION that combines both routes. Main route passes: Eleusina, Megara, Ancient Corinth, Ancient Nemea, Artemisio mountain (1,227m), Sparta. Marathon extension follows the steps of General Miltiades' army to the Battle of Marathon battlefield. MANDATORY PROGRESSION: Complete Athens-Sparta-Athens portion first, finishing at Ancient Agora within 93-hour cut-off, THEN continue to Marathon with 7-hour time limit for final 39.6km. ELIGIBILITY: 2026 (10th anniversary) - ALL registered runners can attempt. From 2027 onwards - ONLY runners with valid prior finishes eligible. Registration deadline: 30 September 2026. Entry fee: €350 (all periods). Medical certificate (not older than 6 months) required. FINISHER REWARDS: Medal, diploma, commemorative t-shirt, finisher gift. COURSE SUPPORT: 77 feeding stations; 11 main aid stations with hot food, rest facilities, personal supply depots. Electronic chip timing with GPS device (SOS button). SAFETY: Reflective gear, headlamp, rear light mandatory dusk-to-dawn. No hotel stays during race. Support vehicles at official stations only (30m rule). MEDICAL: Full coverage with doctors, paramedics, EKAB; hospitals on alert. Committed to 'green race' environmental standards. Memorial edition honoring Taki Skuli, race creator.