© Shutterstock 

Mount Rainier National Park -

Established in 1899, Mount Rainier National Park is named after the eponymous Mount Rainier, a 4,392-m (14,411-ft) active stratovolcano and the highest mountain in Washington state.

© Shutterstock 

Wonderland Trail -

Mount Rainier is circled by the Wonderland Trail, an approximately 150-km (93 mi-) hiking trail that circumnavigates the iconic peak. The average time taken to complete the entire trip is 10 to 14 days.

© Shutterstock 

North Cascades National Park -

The North Cascades National Park shares a border with the Canadian province of British Columbia, and is one of the region's most popular outdoor destinations. Challenging hiking trails crisscross the landscape. But there are plenty of less rigorous family-friendly treks to follow, too. Mount Shuksan, seen here mirrored in Picture Lake, is one of the most photographed mountain scenes in the state.

© Shutterstock 

Diablo Lake -

This is Diablo Lake, in the North Cascades Mountains. The unique, intense turquoise hue of the lake's water is attributed to the surrounding glaciers that grind rocks into a fine powder, which is then carried into the lake through creeks. Teeming with trout, the destination attracts anglers from across the state. The scenic Diablo Lake Trail runs along the lake's northern shore.

© Shutterstock 

Olympic National Park -

Located on the Olympic Peninsula, Olympic National Park encompasses four regions: the Pacific coastline, alpine areas, the west-side temperate rain forest, and the forests of the drier east side.

© Shutterstock 

Mount Olympus -

The park is named for Mount Olympus (the indigenous-American name of which is Sunh-a-do). At 2,432 m (7,980 ft), it's the tallest and most prominent mountain in the Olympic Mountains range. It's seen here, together with the spectacular Blue Glacier, from Hurricane Ridge.

© Shutterstock 

Hoh Rain Forest -

The park's Hoh Rain Forest sits in a valley formed thousands of years ago by glaciers. One of the largest temperate rain forests in the United States, Hoh's lush, verdant landscape is embellished with maple, cedar, spruce, and fir trees, some reaching 95 m (312 ft) in height and 7 m (23 ft) in diameter.

© Shutterstock 

Hall of Mosses Trail -

Many unique mosses and lichens are also present in the rain forest. One of the most rewarding ways of appreciating this magical environment is to follow the Hall of Mosses Trail.

© Shutterstock 

Roosevelt elk -

During your exploration of Olympia National Park, be on the look out for mighty Roosevelt elk, also commonly known as Olympic elk.

© Shutterstock 

Seattle -

Seattle is the largest city in both the state of Washington and the Pacific Northwest region of North America. A densely-packed city worth several days of your time to turn inside out, Seattle is a rewarding cultural and architectural draw. Get your bearings from the top of Columbia Center, the highest building in the city, which affords a stunning overview of the destination.

© Shutterstock 

Space Needle -

Seattle's Space Needle (pictured) is easily the most iconic building in the city. It was built for the 1962 World's Fair (incidentally featured in the Elvis Presley movie 'It Happened at the World's Fair'). The loft observation deck affords a jaw-dropping panorama of the downtown skyline.

© Shutterstock 

Museum of Pop Culture -

Seattle has a noteworthy musical history. It's the birthplace of Jimi Hendrix, as well as the origin of the bands Nirvana, Pearl Jam, and Soundgarden. Celebrate this harmonious heritage by browsing Seattle's fabulous Museum of Pop Culture. The facility, designed by celebrated architect Frank Gehry, is dedicated to contemporary popular culture and will definitely strike a chord with anyone into music.

© Shutterstock 

Museum of Flight -

The Museum of Flight is located in Tukwila, immediately south of Seattle. This the largest private air and space museum in the world and has more than 150 aircraft in its collection. Exhibits include Caproni Ca.20, the world's first fighter plane from the First World War (and the only one ever built), and a Boeing VC-137B, the first presidential jet.

© Shutterstock 

San Juan Islands -

Back in the great outdoors, the San Juan Islands are an archipelago anchored between Washington state and Canada's Vancouver Island. Pictured is the historic Patos Island Lighthouse in front of the majestic-looking Mount Baker.

© Shutterstock 

Whale-watching -

The San Juan Islands are noted for their orca whale-watching opportunities, either by boat or by air. San Juan Island's Lime Kiln Point State Park is a prime whale-watching site.

© Shutterstock 

Watersports activities -

The four largest of San Juan's islands are accessible by ferry. Each is served by a number of campgrounds, restaurants, and cafés. Besides whale-watching, sea kayaking is a favorite pastime.

© Shutterstock 

Mount St. Helens National Volcanic Monument -

Washington state's most notorious mountain is this one, Mount St. Helens. On May 18, 1980, the active volcano literally blew its top to reduce the peak by 396 m (1,300 ft). Visitors can learn more about this calamitous event (57 people lost their lives) by reading the information panels set along the many hiking trails that skirt the mountain. It's also possible to climb Mount St. Helens, but only with prior permission.

© Shutterstock 

Okanogan–Wenatchee National Forest -

Okanogan–Wenatchee National Forest is bordered on the north by British Columbia and is one of the largest national forests in the United States. Pictured is a view of the picturesque Theseus Lake.

© Shutterstock

Olympic marmot -

Look out for this little guy on your travels. It's an Olympic marmot. Indigenous to Washington state, it's only seen on the middle elevations of the Olympic Peninsula. About the size of a domestic cat, this large rodent is the official state mammal.

© Shutterstock 

Leavenworth -

Tourists from central Europe will feel right at home in Leavenworth. The entire town center is modeled on a Bavarian village. Jump aboard a horse-drawn carriage for a romantic tour of the town's narrow streets before relaxing at a sidewalk café over a weissbier or two.

© Shutterstock 

The Deception Pass Bridge -

Spanning Whidbey and Fidalgo Islands in Puget Sound, the Deception Pass Bridge is an iconic landmark of the Deception Pass State Park. The park is noted for a wealth of recreational activity options, including tidepooling, hiking, and boating. Excellent nearby campsites solve the accommodation dilemma.

© Shutterstock 

Spokane River Centennial Trail -

Spokane, in eastern Washington, benefits from a dryer, sunnier climate. Set along the Spokane River, the city exudes a pleasant, laid-back air. First-time visitors should follow the semi-urban Spokane River Centennial Trail, part of which snakes through the city and passes several iconic buildings. Alternatively, take the cable car and cross the Upper Spokane Falls for a wonderfully different introduction to the destination.

© Shutterstock 

Bellingham -

Lying north of Seattle, attractive Bellingham is the gateway to the San Juan Islands and the Northern Cascades. The city itself is known for outdoor attractions such as Whatcom Falls Park, with its four sets of falls and numerous walking trails. Bellingham is also a useful base from which to explore the Skagit Valley.

© Shutterstock 

Skagit Valley Tulip Festival -

Time your Washington state vacation for April and you'll be able to take in the vibrant color and intoxicating bouquet that is the Skagit Valley Tulip Festival. It takes place annually April 1 to April 30.

© Shutterstock 

The Pacific Crest Trail -

Weaving its way through the entire state is the Pacific Crest Trail, a long-distance hiking trail reckoned by many to be one of the toughest in the world. But you don't have to be a seasoned hiker to enjoy a walk along this legendary track—some of the best day hikes on the Pacific Crest Trail span Washington, Oregon, and California.

© Shutterstock

Museum of Glass -

Here's a novel diversion. The Museum of Glass in Tacoma is dedicated to all things made using glass. Many of the pieces on display have been crafted by Tacoma native and renowned glass artist Dale Chihuly. The museum building, designed by renowned Canadian architect Arthur Erickson, is recognized for its distinctive angled cone shape.

© Shutterstock 

Olympia -

Olympia, the state capital, is set against the southern end of Puget Sound. An array of parks lend the city an almost pastoral air. The obvious cultural highlight is the Washington State Capitol building, itself set in a pleasant tree-lined green space. A tour of the interior is worthwhile to see the lavish features, including a huge glittering Tiffany chandelier.

© Shutterstock 

Puget Sound -

Bordering the western edge of the state, Puget Sound, an inlet of the Pacific Ocean, is filled with inlets, islands, and outcrops of rock. This watery environment allows for easy day trips and island-hopping, a variety of watersports options, and whale-watching excursions.

© Shutterstock 

Fort Vancouver National Historic Site -

Standing guard over the Washington city of Vancouver on the northern banks of the Columbia River is Fort Vancouver. Once a major center of the regional fur trade, the fort also served as a barracks for the United States Army in the mid-19th century. The original structure is long gone. What you see today is an authentic replica, which in fact consists of two units: one in Vancouver, the other in neighboring Oregon.

Sources: (National Park Service) (Architectural Digest) (US History) (Washington Education)

See also: Why you should see the least-visited US national parks

© Shutterstock