If you're experiencing issues with Civilization 5 after the 6/14/2012 patch, please try the following troubleshooting steps to help resolve the issue.
•Make sure all drivers are up to date for your PC, specifically your graphics card drivers. Running the game on old graphics card drivers can cause a wide variety of problems.
•Make sure you have the most recent version of DirectX installed.
•Delete the files in the following folder: \My Documents\My Games\Sid Meier's Civilization 5\cache\. As well as config.ini, GraphicsSettingsDX9.ini and GraphicsSettingsDX11.ini in \My Documents\My Games\Sid Meier's Civilization 5\
•Right click on the game in Steam, select properties, select local files, and select “Verify Integrity of Game Cache…”
•While troubleshooting, try disabling any mods that are currently active; especially after the patch, some more intensive mods that haven’t caught up to the updates may cause issues for general gameplay.