A twin skyscr is under construction.?

The twin building will end up about 2.5 km in the sky with added spire of 150 meters. The problem is, once it reach the height of 800 meters, the twins slip from vertical in a quite small distance. The correction took place and its back to vertical. Once the project completed, will both towers lean inward or outward? How it will look like if the horizon is really flat?