As the decades-long chill in U.S.-Iran relations begins to thaw, the Eurasian Republic is quickly becoming one of the most sought-after travel destinations of the year. The country boasts extraordinary contemporary architecture -- designed, no less, by an impressive cadre of largely female architects -- many of the world's oldest cultural monuments, and vast frontiers unseen by most Western eyes.

Given that the U.S. only lifted sanctions on Iran a few months ago, you might not expect travel to be as plush as it is in more popular destinations. But these two luxury tour groups are taking the best of the country's breathtaking sites and packaging them into extensive itineraries that make tackling Iran easy and comfortable.

By Train

Golden Eagle Luxury Trains is offering The Silk Road and Persia trip, an epic 18-day voyage along the Silk Road to the capital of Tehran, whilst passing through Russia, Kazakhstan, Uzbekistan, and Turkmenistan en route to the great Iran. The pioneering trip reaches some train-only areas, which gives the trip an edge over standard tours. Highlights include the space station at Baikonur, the oldest Koran at Tashkent, the ruins of Konjikala (where Ashgabat, the Las Vegas of the Karakum desert, is today), as well as UNESCO cities Bukhara and Khiva, and the famed mud brick citadel at Rayen.

By Road

Abercrombie & Kent have revealed their own itinerary for Iran. The company's small group journeys cover landmark sites, preserved over the course of the country’s 5,000-year-old history, and many of Iran's 19 UNESCO World Heritage sites -- all in a 4x4. On the agenda: the ancient city of Ahvaz, the architectural splendor of Isfahan (Iran's equivalent to Machu Picchu or Angkor Wat), the ruins of Persepolis, and the gardens of Shiraz.

How to get there

This week, Air France joined the list of European carriers servicing Iran. Alitalia, Lufthansa, and Austrian Airlines were the first European carriers to relaunch service to Tehran after the sanctions were lifted, and British Airways is expected to resume its London-Tehran route this July.