The United States and other countries have placed sanctions on a number of Russian oligarchs, who are seen as major financial and political supporters of Vladimir Putin. Among the oligarchs is Roman Abramovich, the multi-billionaire owner of the Chelsea Football Club, one of the United Kingdom’s top soccer teams. Abramovich is Jewish and also holds Israeli citizenship. Just weeks ago he made a $3 million donation to Yad Vashem, Israel’s Holocaust Memorial Museum. On February 6, Yad Vashem chairman Dani Dayan, as well as Ashkenazi Chief Rabbi David Lau and many other Israeli leaders, sent a letter to the United States Ambassador to Israel asking that Abramovich not be sanctioned because of “his contribution to the Jewish people.” But on March 10, Yad Vashem issued a statement saying, “In light of recent developments, Yad Vashem has decided to suspend the strategic partnership with Mr. Roman Abramovich.” Many of the oligarchs have put some of their money into superyachts, which in some cases have been seized as part of sanctions. Both of Abramovich’s superyachts are currently cruising with no clear destination, hoping to avoid seizure. What are the names of Abramovich’s two superyachts (each of which is worth at least $600 million)?