Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding is recommended. First your game file, which is by default in Documents\My Games\Sid Meier's Civilization 5. Then, with a text editor, edit the "config.ini" file in the game directory. Change the DebugPanel = 0 line to DebugPanel = 1. Start a new game and press ` or ~ and and a debug panel with various options will appear on the right side. For example, select the "Reveal All" option to view the full map.