The 2,650-acre campus of the Smithsonian Environmental Research Center (SERC) in Edgewater, Maryland, encompasses a mix of forests, farmland, wetlands, and shoreline and is home to some of the world’s most enduring environmental research projects. Spend the day with SERC’s expert staff as you explore this environmental research hub and learn about its cutting-edge ecological studies.

Historic Garden Week in Virginia offers the opportunity to visit beautiful homes and gardens in the state, ranging from classic to modern. Horticulturist Chelsea Mahaffey leads this tour of Oak Spring, the former home of philanthropists Paul Mellon and Rachel “Bunny” Mellon which is usually closed to the public, and the University of Virginia’s Blandy Experimental Farm, which includes the State Arboretum of Virginia.

From the desert gardens to the red rocks of Sedona, the northern mountains to the depths of the Grand Canyon, this 6-day spring adventure offers outdoor enthusiasts an itinerary filled with education and scenic beauty led by geologist and study tour leader Wayne Ranney.

Assateague Island National Seashore and Chincoteague National Wildlife Refuge are home to natural splendor, cultural treasures, and coastal charm. Spend two days with naturalist and educator Liana Vitali immersed in island life, exploring the natural wonders the barrier islands have to offer—and hear the lore of the Chincoteague ponies’ origin.

Washington, D.C.'s Southwest Waterfront is a study in contrasts: The neighborhood retains some of the most historic architecture in the federal capital and boasts one of the largest private development projects in the city, the District Wharf. Laid out by the Carroll family in the 1770s, the neighborhood teemed with commercial activity by the 1830s. In the mid-20th century, huge swaths of the area were demolished in the name of urban renewal. Carolyn Muraskin, founder of DC Design Tours, leads a tour of the historic neighborhood.