I am bumping this thread in hopes of seeing some more non-USA advertising covers.
Here is one which was very unloved and damaged. I fished it out of a dollar box at a show many years ago with the idea that I would fix it up a bit and make it a little more presentable. That happened today.
The cover was sent from Weissenburg (Bern canton), Switzerland to Southport, North Carolina on June 25, 1900. The sender wrote "Via Oceanic, Liverpool" at the top of the cover.
Weissenburg has a mineral springs spa which has been in use since 1604. The pictures on the cover show what looks to be a resort. According to Wikipedia, "A magnificent building was operated from 1898 to 1939, and burnt down in 1974."
The RMS Oceanic was a steamship built in Belfast, North Ireland for the White Star Line. Her maiden voyage was on September 6, 1899. Per Wikipedia, "...was the largest ship in the world until 1901."
Southport, North Carolina is a coastal town below Wilmington. The transit cancel on the reverse of the cover is Red Springs, N.C., July 7, 1900. Red Springs is an inland village below Fayetteville.