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.
Europe is great and Asia is awesome, but the song says America the beautiful. These hidden places prove you don't need to spend big bucks and make a transatlantic trek-- the world's most beautiful wonders have been here all along, right in your American backyard. Grand Prismatic Spring in Yellowstone National Park, Wyoming. Fur trappers stumbled upon this boiling lake less than 200 years ago.