I was playing a server which consists of insane builds. I wanted to download these maps, but when I tried the world downloader mod, it does not work. Is there a solution to download it without using any mods?
You can't download server worlds without mods, however if you are willing to use mods i recommend Schematica http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/1285818-schematica
Before downloading anything contact the creator for permission