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.
Image by yeowatzup via Flicker. The capital of Russia and indisputably one of the worldâs most financially powerful cities, Moscow is home to the highest amount of the worldâs billionaires and to Gazprom, the worldâs largest natural gas exporter.