Six countries produce nearly 60 percent of global carbon dioxide emissions. China and the United States combine for more than two-fifths. The planet's future will be shaped by what these top carbon polluters do about the heat-trapping gases blamed for global warming. How they rank, what they're doing:
Viking River Cruises Tipping Policy. It is customary to give cruise gratuities, subject to your satisfaction of services rendered. Gratuities on board and on land are not included in your full fare.
Tipping is prohibited at National Park Service and similar government sites. If you are on a multi-day package tour that uses different bus drivers and other modes of transportation, speak with your tour manager about the tipping policy. He may prefer to handle tipping for the entire group.