Midwest: Chicago, Detroit, Duluth, Mackinac Island
Northeast: Boston, Philadelphia, New York City, Niagara Falls, Washington, D.C.
West (Interior): Badlands and Black Hills, Mount Rushmore, Devils Tower National Monument, Theodore Roosevelt National Park, Yellowstone National Park
West Coast: Columbia Gorge, Olympic National Park, Oregon Coast, Portland, Redwood National Park, San Francisco, Seattle

British Columbia: Vancouver, North Shore, Bowen Island
Ontario: Toronto, Niagara Falls, Windsor
Quebec: Montreal, Quebec City

England: London, Salisbury, Stonehenge
France: Paris
Germany: Berlin, Munich, Potsdam
Ireland: Dublin, Belfast
Italy: Rome, Venice
Netherlands: Amsterdam

New Orleans, Pittsburgh, California's Central Coast.

Vancouver Island, Ottawa, Halifax. I'd also like to travel across the entire country by train.

Amalfi Coast, Athens, Barcelona, Cinque Terre, Cologne, Copenhagen, Dresden, Edinburgh, Florence, Glasgow, Hamburg, Istanbul, Lisbon, Madrid, Naples, Prague

Buenos Aires, Havana, Mexico City, Rio de Janiero, Sao Paulo, Santiago de Chile, Teotihuacan, Valparaíso

Bangkok, Hong Kong, Istanbul, Tokyo

Cairo