The first Earth Day was celebrated on April 22, 1970. We mark it again this Saturday. Decades after that optimistic first event, the National Oceanic and Atmospheric Administration reminds us that “global climate change has had an alarming effect on Earth and its inhabitants.” Waves upon waves upon yet more waves of tourists crisscrossing the globe have helped contribute to the environmental stresses. But you don’t have to totally cut out travel or stay super close to home to be a good planetary citizen. You can still tour the world and still minimize the impact on the health of our one and only (and vulnerable) planet. Check out these five ways to more gently explore the Earth: Sustainable ships Cruising is an industry known for its carbon-discharging vessels, waste production spanning from trash to gray water and overcrowding in ports of call. However, you don’t need to give up your dreams of oceanic adventure to be a good steward of the environment. Click here to find out how Hurtigruten, Ponant, Star Clippers and other cruise lines are easing pressure on the seas. Hiking You might burn some fossil fuels to get there, but once you’ve arrived, hiking is all about burning up calories. But where to go for an epic hike? CNN Travel has 23 of the best hikes in the world, including Camino de Santiago de Compostela (Spain), the Appalachian Trail (United States), the Basho Wayfarer (Japan) and the Lycian Way (Turkey). Greener ski resorts The infrastructure that supports the exhilarating sport of snow skiing adds its own pressures to our warming planet. Some resorts are trying to reduce their environmental impact, such as using renewable energy to run their lifts. From Val d’Isere (France) and Jackson Hole (Wyoming) to Zermatt (Switzerland) and Whistler (Canada), here are 10 places where you can ski with an eased mind. Bicycles Not only are bicycles easier on the environment, they let you get up close and personal with cities in a way that’s just about impossible from vehicles. But not all cities that tourists enjoy are bicycle friendly. You need a city that’s dedicated to getting it right to best enjoy an urban biking vacation. From Antwerp and Melbourne to Montreal and San Francisco, check out these 10 cities where bicycling works. Inspiration from a beautiful planet Sometimes, Earth’s sheer incredible beauty and wildly varied landscapes can move us to think about better protecting the planet. And what a beautiful world it is, whether you’re taking in the landscapes of lush Brazil, the green-hued charms of Ireland, the boundless sweep of Canada or the gorgeous scenery of Vietnam.