Exxon Mobil Corporation CEO Rex Tillerson and Russia's Prime Minister Vladimir Putin (L-R front) during a meeting at Novo-Ogaryovo residence, April 16, 2012. (Alexei Nikolsky\TASS via Getty Images)
Republican presidential candidate Donald Trump (L) looks on as Egyptian President Abdel Fattah el-Sisi speaks during a meeting at the Plaza Hotel on September 19, 2016 in New York. (DOMINICK REUTER/AFP/Getty Images)
Flowers are placed in front of a portrait of Russian Ambassador to Turkey Andrei Karlov in the Foreign Ministry in Moscow on December 20, 2016, a day after his assassination in the Turkish capital. (NATALIA KOLESNIKOVA/AFP/Getty Images)
Atef's grandchildren present on their right wrist the tattoo of a blue cross, a sign of their belonging to the Copts of Egypt, Cairo, November 9, 2010. (Alvaro Canovas/Paris Match via Getty Images)
A nun reacts to the scene of a bomb explosion at the Saint Peter and Saint Paul Coptic Orthodox Church on December 11, 2016, in Cairo's Abbasiya neighbourhood. (KHALED DESOUKI/AFP/Getty Images)
Broken windows are seen after an explosion at Saint Mark's Coptic Orthodox Cathedral in Cairo, Egypt on December 11, 2016. (Ahmed Gamil /Anadolu Agency/Getty Images)