'Fenced' in the Bible

whither are we going up? our brethren have melted our heart, saying, A people greater and taller than we, cities great and fenced to heaven, and also sons of Anakim -- we have seen there.

All these cities were fenced with high walls, gates, and bars; beside unwalled towns a great many.

Hear, O Israel: Thou art to pass over Jordan this day, to go in to possess nations greater and mightier than thyself, cities great and fenced up to heaven,

And he shall besiege thee in all thy gates, until thy high and fenced walls come down, wherein thou trustedst, throughout all thy land: and he shall besiege thee in all thy gates throughout all thy land, which the LORD thy God hath given thee.