Fortran
The first high-level language to see wide adoption, released by IBM in 1957 with John Backus leading the project. The name comes from Formula Translation. Still the king of scientific computing.
The original selling point was that the compiler generated code nearly as fast as hand-written assembly, which few believed possible. FORTRAN 77 is the version many remember, with punch card columns and GOTO; Fortran 90 introduced free-form source, modules and array operations on whole matrices, and the standard has been updated regularly since. Its survival comes down to three things: compilers optimize aggressively because the language lacks pointer aliasing, the LAPACK and BLAS libraries are written in it, and fifty years of validated numerical code in climate models, fluid dynamics and nuclear physics doesn't get rewritten without cause.