Endless US tours turned Led Zeppelin into a powerhouse.

Absolutely. Their early touring schedule is the main reason they sounded like that.

Between January 1969 and late 1970, Led Zeppelin played something like 130 shows in the US alone — sometimes four or five nights in a row in different cities. That’s not a luxury tour. That’s a boot camp. They were sleeping on floors, driving between gigs, playing clubs and ballrooms to crowds that sometimes didn’t know who they were. The only way to survive was to get tight as a unit and learn to read a room instantly.

That schedule forced them to become a live band first, studio band second. They couldn’t rely on overdubs or production tricks on stage. So they developed a raw, extended, improvisational style — Page’s solos became longer, Bonham’s drums got heavier, Plant learned to work a crowd. Listen to any early bootleg from 1969 and you’ll hear a band that’s already locked in, pushing each other, adapting on the fly. The studio albums capture