Filmgoers today are so inured to CGI special effects that they forget how things were in cinema just a couple of decades ago. Way before CGI, a technique called matte painting was used to create the desired effects on film that would otherwise be extremely expensive or outright impossible. A good example is the closing shot of 1981's Raiders of the Lost Ark, as a nameless worker wheels the crated Ark to a distant location inside of an unnaturally immense government warehouse.
The fact that the public never really knew anything about the deliberately concealed trickery was thanks to overly protective studio bosses who often went all out to deny that the wonders up on that silver screen were anything other than great insightful film making. Those same studio tyrants did their utmost to try to prevent the Academy of Motion Picture Arts and Sciences from establishing a category for special effects.
The story of the matte painting wizards and many samples of their work, including some that will be a surprise to you, may be found here.