I remember one night way down in eastern Maine I was listening to a station in DelRio Texas
That station in Del Rio had (has?) its transmitter across the border in Mexico where there was (is?) no limit on transmitter power, so it used to crank out about nine-umpty gazillion flabblewatt signals. Since it was an AM station at the low end of the band, it could "skip" about half way around the globe on a good night.
I picked it up in Boston fairly regularly in the late '50s and early '60s, but they didn't really crank up the watts until local AM stations elsewhere in the US mostly went off the air, so it was usually around 03:00 in Boston (after midnight in Del Rio) before it started to come in.