This Stack Overflow article covers the subject well:
This is a slightly modified example:
$ find . -type f -printf "%T@ %p\n" | sort -n | cut -f2- -d" " | tail -7 ./dir_a/README.md ./dir_a/hello.java ./dir_b/README.md ./dir_c/README.md ./dir_c/subdir/src/Hello.js ./dir_c/subdir/src/Goodbye.js ./cached-dir_a/README.md