USA is a wide and still wild country. From Pennsylvania to Arizona there are many things to discover: culture, food, museums, economics, politics, science, medicine, cinema and theater... There are lots of ways to discover the US in other ways we usually do.
Shale gas is natural gas, whose deposits are found in shale rocks. For a decade, the U.S. gas industry has observed a rapid growth in shale gas production.
The most significant shale growth happened in Pennsylvania, in theMarcellus Shale.
