• Gros Morne National Park in Newfoundland is just one of nearly 100 parks and historic sites accessible for free for two years to Canadians with a 2016 Discovery Pass. (Photo: Miriam Koerner/CanGeo Photo Club)

If you've been waiting for the perfect time to plan some adventures in Canada's national parks, now's your chance.

On Monday, Parks Canada announced that it will be offering free access to its parks in 2017. All Discovery Passes sold in 2016 will be valid for 24 months from the date of purchase instead of the regular 12 months. For example, a pass purchased in February 2016 will be valid through February 2018.

The Discovery Pass grants the bearer unlimited access to nearly 100 national parks, marine conservation areas and historic sites across the country.

Parks Canada spokesperson Natalie Fay said in an email that extending the Discovery Pass for two years is just one way the organization plans to celebrate Canada's 150th birthday in 2017. More details will be announced as the sesquicentennial draws closer, but Fay said Canadians should expect that national parks will play a huge role in the yearlong celebration.

Discovery Passes are on sale now; for more information or to purchase your pass, visit Parks Canada. Explore the map below to see participating sites.