Turkey's major cities—Istanbul, Izmir, Antalya, Ankara—are important to know, but also its regions (Thrace/Marmara, Aegean, Mediterranean, Cappadocia, etc.)
Turkey is 1565 km (970 miles) east to west and 550 km (400 miles) north to south at its widest points.
Click on a name for more info (which will open in a new browser window so you can still see the map).