President Obama’s landmark nuclear agreement with Iran may still have a long road ahead, but that hasn’t prevented travelers from eyeing the history-rich destination. Attractions range from the modern capital of Tehran to the ancient literary city of Shiraz. If you’re a U.S. citizen and Iran is on your travel short list, be sure to plan at least six months in advance, advises Linda De La Torre, Geographic Expeditions’ Director of Middle East and Africa. “Travel to Iran has become increasingly popular over the last few years. It’s putting a high demand on the country’s limited tourism infrastructure.” You’ll need extra time for the complicated visa process, which can take 90 days or longer and requires a confirmed itinerary through a tour provider. One last caveat: If your passport has an Israeli visa or stamp, you’ll need to replace it.