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 the Marcellus Shale.
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.