Though tensions between Iran and the United States have escalated since President Trump took office, the appeal of Iran for adventurous travelers is obvious: the monumental ruins of ancient Persia, the spectacular, centuries-old mosques of Shiraz and Isfahan, the Grand Bazaar and Golestan Palace in the bustling metropolis of Tehran. One additional reason to visit in 2019 is a major exhibition scheduled to open at the Tehran Museum of Contemporary Art, a popular hangout for young Iranians. “Portrait, Still-life, Landscape” (Feb. 21 to April 20) will take over the entire museum, with a selection of about 500 works, including pieces by Andy Warhol, Mark Rothko and Marcel Duchamp, as well as about 40 Picassos recently discovered in the museum’s storage facilities (much of the collection has been kept under wraps in the decades since the 1979 revolution). The United States State Departmentdiscourages, but does not prohibit, travel to Iran by American citizens, and Americans can travel to Iran only as part of an organized tour. Some options for 2019 include three expeditions from Intrepid Travel, including the company’s first-ever all-female tour as well as guided tours by the high-end British travel operator Cox & Kings.