In most cases, pulmonary embolism is caused by a blood clot in the leg that breaks loose and travels to the lungs. A blood clot in a vein close to the skin is not likely to cause problems. But having blood clots in deep veins (deep vein thrombosis) can lead to pulmonary embolism.
St. Petersburg. 1  St. Petersburg is a city with a long and eventful history. 2  Altai is perhaps the most beautiful region of Russia. 3  Moscow is the capital of Russia, as well as the nationâs epicentre of arts, music, science, academics, and politics.  For a step back in time, Olkhon Island is a wonderful place to visit.
Amazing historical and cultural sites await passengers who cruise this magnificent region, and shore excursions typically visit museums, palaces, castles and cathedrals. Stroll cobblestone streets amid medieval architecture in the well-preserved Baltic capitals of Riga, Latvia, and Tallinn, Estonia. Visit St. Petersburg's legendary Hermitage, considered one of the world's greatest museums, and spend time touring some of Russia's most notable grand palaces.