I like Wikipedia and found an interesting quote…
As the Victoria era came to an end, the influences of the industrial revolution created more and more varied members of the upper middle class. The concepts of vacationing, tourism, and travel became less the property of the old monied, and shared by an increasing population base of those who could afford holiday trips like the rich. Such adventures had much allure in the days before any audio-visual entertainments outside a live orchestra. Thus, the spas began attracting an increasing number of local patrons as well as those from afar just at the time when the burgeoning numbers were able to take advantage of the newfangled automobile and the now extensive railways throughout most all of Europe and the United States. The Spa towns already had infrastructure and attractions in place to assuage such desires, and the modern tourist trip began to take its familiar form. Other technologies came into play (Ski’s, Ski boats, etc.)
The timing of the Great Depression varied across nations, but in most countries it started in about 1929 and lasted until the late 1930s or early 1940s.