For completeness, there are languages that do not require stacks to implement (nor any workarounds that in practice emulate a stack). If you do not support explicit recursion, you don't need one. All variables can be statically allocated and only a single return address needs to be stored for each function, so you do not need a stack for return addresses either.

The most famous example is FORTRAN, until 1990 when they added RECURSIVE directive.