1.Badaling (八达岭): The most famous and most visited section, closest to Beijing (60km). Features well-preserved architecture but gets very crowded, especially on weekends and holidays. Mutianyu (慕田峪): Scenic and less touristy, with lush greenery and a longer stretch of original walls. Ideal for photography and peaceful hikes, located 73km from Beijing. Juyongguan (居庸关): A historic military hub with a more rugged, less restored appearance. Popular for its dramatic mountain views and fewer crowds, suitable for experienced hikers. 2.Timing: Visit on non-holidays (avoid Chinese National Day, May Day) or arrive before 9:00 AM/after 3:00 PM to miss peak hours. Section Choice: Choose Mutianyu or Jinshanling (金山岭，a more remote section) – both offer cable cars/toboggan rides to skip crowded hiking paths. Transport: Take private cars or tour buses instead of public transport to reach early. 3.Yes, during peak season (usually April–October), but requires separate reservation via the official Badaling app or website. Night tours include illuminated sections and cultural performances, ideal for unique photo opportunities. Book in advance as slots fill quickly.