There are now, but BASIC was invented in the 70's, and some very powerful versions of it were used to build just about everything in the 80's and even the 90's. There was BBC Basic on the BBC micro, GFA Basic on the ST and of course MSVB on the PC, which if you have windows is most likely still lurking in your system somewhere.
Each of those could be used to write very complete applications including GUIs and such.
Each of those could be used to write very complete applications including GUIs and such.