2 Kings 17:9

9 The Israelites secretly did things against the LORD their God that were not right. From watchtower to fortified city they built themselves high places in all their towns.

Read 2 Kings 17:9 Using Other Translations

And the children of Israel did secretly those things that were not right against the LORD their God, and they built them high places in all their cities, from the tower of the watchmen to the fenced city.
And the people of Israel did secretly against the LORD their God things that were not right. They built for themselves high places in all their towns, from watchtower to fortified city.
The people of Israel had also secretly done many things that were not pleasing to the LORD their God. They built pagan shrines for themselves in all their towns, from the smallest outpost to the largest walled city.