English: Rome wasn't built in a day.

There are lots of variations on the "Rome was not built in a day" saying; Carol Dweck even mentions it in her Mindset book:

We have lots of sayings that stress the importance of risk and the power of persistence, such as “Nothing ventured, nothing gained” and “If at first you don’t succeed, try, try again” or “Rome wasn’t built in a day.”

I grabbed a Rome version from Sue's Cheezburger gallery (see below), and here is a Polish version about the lovely city of Cracow from my Proverb Laboratory:

Cracow wasn't built in a day.

(Polish: Nie od razu Kraków zbudowano.)

From Sue Strickland's Cheezburger gallery:

Roma aedificata est non uno die.

And here's an English version that I made with AutoMotivator with a photo by Robert Lowe: