Meet the empty nesters who have visited all 63 US national parks - after realising 'life is too short'.

Matt, 63, and Karen Smith, 64, became empty nesters 16 years ago when their youngest son, now 35, moved out.

After losing friends and family of a similar age - the couple realise that life is too short.

They set themselves the challenge of visiting every US national park and spent two years seeing them all.

The couple have sailed down the Grand Canyon, seen wild bison at Yellowstone National Park and breath-taking views at Canyonlands National Park.

Now they are going back and visiting all the parks they have previously been to.

Karen, a travel content creator, from Seattle, Washington, said: "We had just become empty nesters. We have three kids and our youngest went off to college."

"We realised that we didn't have to be home all the time. Matt also has a new corporate job that he wasn't particularly happy with."

"We were 50-years-old at the time and we had close friend's and family pass away."

"All of a sudden, we realised our mortality and that if we wanted to visit all these national parks now was the time."

Matt and Karen set off on their incredible adventure in the spring of 2010 and managed to visit all of the then 58 national parks within two years.

Matt, a travel content creator, said: "We started off by visiting national parks close to our home."

"We went to North Cascades National Park and brought some of our adult kids to get us started."

"We did not buy AN? RV and travel around the country, we either drove from Seattle or flew." "

Since completing their goal to visit all of the then 58 national parks in 2012, the US Government added five more parks for Matt and Karen to visit - taking the new total to 63.

Matt and Karen both agreed that one of their favourite national parks to visit is Yellowstone due to its nature and "epic views"."

Matt said: "Yellowstone is incredible for a lot of reasons."

"When we are in Yellowstone we are seeing bison, which is the emblem of North America."

Karen added: "It feels like a wilderness park."

"You can look out your window and see a grisly bear with its cubs or wolves and spot bison."

"It is one of the most unique experiences I have ever had."

The adventurous couple said that one of their favourite trips was when they sailed down the Colorado River, through the Grand Canyon in WHEN.

Matt said it was a "life time experience" that changed their lives."

He said: "It was a once in a lifetime experience, we were seeing the canyon from the bottom and now how other people see it from the top."

"We spent 16 days on the river. It is just you, your team and your friends that you were going with."

"We were at peace with nature - it was a completely different experience."

Before they set off travelling around the United States, the couple would usually vacation in Europe.

Karen said visiting the national parks has allowed them to fall in love with a different side of America.

She said: "We had almost seen every country in Europe but we never really saw what was in our own back yard."

"We discovered what is beautiful about our country, before we had done this we wouldn't have been able to name all the national parks and now we have visited them."

"The discovery of our country was just huge for us - it is such a life changing experience."

List of US National Parks they've visited -
Acadia National Park
Biscayne National Park
Congaree National Park
Dry Tortugas National Park
Everglades National Park
Great Smoky Mountains National Park
Hot Springs National Park
Mammoth Cave National Park
New River Gorge National Park and Preserve
Shenandoah National Park
Virgin Islands National Park
Big Bend National Park
Carlsbad Caverns National Park
Grand Canyon National Park
Guadalupe Mountains National Park
Petrified Forest National Park
Saguaro National Park
White Sands National Park
Badlands National Park
Cuyahoga Valley National Park
Gateway Arch National Park
Indiana Dunes National Park
Isle Royale National Park
Theodore Roosevelt National Park
Voyageurs National Park
Wind Cave National Park
Arches National Park
Black Canyon of the Gunnison National Park
Bryce Canyon National Park
Canyonlands National Park
Capitol Reef National Park
Channel Islands National Park
Crater Lake National Park
Death Valley National Park
Glacier National Park
Grand Teton National Park
Great Basin National Park
Great Sand Dunes National Park
Joshua Tree National Park
Kings Canyon National Park
Lassen Volcanic National Park
Mesa Verde National Park
Mount Rainier National Park
North Cascades National Park
Olympic National Park
Pinnacles National Park
Redwood National Park
Rocky Mountain National Park
Sequoia National Park
Yellowstone National Park
Yosemite National Park
Zion National Park
Denali National Park
Gates of the Arctic National Park
Glacier Bay National Park
Haleakalā National Park
Hawaii Volcanoes National Park
Katmai National Park
Kenai Fjords National Park
Kobuk Valley National Park
Lake Clark National Park
National Park of American Samoa
Wrangell-St. Elias National Park