A more thorough explanation:

tutus accessus non fuit

There was no safe way to get to a place.

• During the war, tutus accessus non fuit to many cities in Europe.
• The mountain was so steep that tutus accessus non fuit to the top.

These examples show situations where it was not safe to access a place. In the first example, the war made it dangerous to go to many cities in Europe. In the second example, the steepness of the mountain made it unsafe to climb to the top.