Layovers can be pretty pesky, especially when you're traveling internationally. However, some airlines are offering travelers an opportunity to take advantage of those layovers with a stopover.

Stopovers are layovers that last more than 24 hours. They're set up through specific airlines and allow travelers to become tourists in the city they have to stop in to get to their destination. Some airlines offer additional perks when you schedule a stopover such as free hotel stays and entry into major attractions.

Check out these 20 cities you can explore with an airline stopover program.

Those who have a six-hour or longer layover with Air Canada can explore what the locals lovingly call the 6ix for free one night and with a discounted hotel stay. Toronto offers a great sports scene, thrilling attractions like the CN Tower, and museums like the Royal Ontario Museum. Don't miss out on their dining scene in Kensington Market or a peameal bacon sandwich at the Carousel Bakery inside the St. Lawrence Market.

The Emirates Airways stopover package in Dubai includes hotel booking from one of 99 hotels, airport transfers, and visa assistance. Emirates will also book cultural tours, desert adventures, theme park tickets, or a dinner reservation at a local restaurant in Dubai under their stopover program.

Iceland is one of the hottest destinations to visit right now and with a free stopover pass in Reykjavik, tourists have a chance to see the Northern Lights, explore the city, relax in one of the hot springs like the Blue Lagoon, or drive through the countryside full of volcanos, lava fields, and glaciers at no extra cost with Icelandair.

With a Singapore Airlines ticket and a stop in Singapore, travelers can explore the tropical and multicultural city on a free stopover. The airline's stopover holiday package is an additional fee but provides perks like a single hotel night stay, access to over 20 attractions, and free rides on the SIA Hop-on bus which takes travelers to Singapore's most popular places and cultural centers.

Explore the ancient history of Rome with Alitalia's three-night stopover program at no additional charge. It's only available through December 31, 2018, so be sure to book right away for a short Roman adventure that can include visits to the Trevi Fountain, Colosseum, and the Vatican.

As the capital of the UAE, Abu Dhabi is world-renowned for its shopping centers, theme parks, and iconic landmarks like the Sheikh Zayed Mosque. With Etihad Airways, travelers can add a two-night stopover in Abu Dhabi. With two-for-one deals on hotels and activities through Etihad Airways, travelers can see all the best that Abu Dhabi has to offer.

Qatar Airways wants to introduce travelers to the capital city, Doha, with their stopover program. Their one-night free stopover program includes a hotel stay and offers visitors an opportunity to see a centuries-old market like Souq Waqif, explore the Museum of Islamic Art, or walk the Doha Corniche water-front promenade.

Finnair's stopover program in the waterfront capital of Helsinki is quite phenomenal. Visitors can extend their layover to a five-day stay and see historic landmarks like the Helsinki Cathedral and Suomenlinna, a UNESCO-listed fortress, and try an array of Finnish foods like pea soup, Baltic herring, and salted licorice.

With Air Canada, you can stop in Montreal for a historic and neighborhood-focused free one-night stopover. See the city's French origins in Old Montreal and take a tour of the Notre-Dame Basilica. Later, shop through the Plateau neighborhood and eat at one of their many restaurants. If you have time, hit up the Olympic Park Complex to explore the Botanic Gardens.

TAP Portugal is bringing more visitors to Lisbon with their stopover program. Tourists can extend their stopover for up to five days in the hilly capital with discounted prices for hotels and activities. A stopover in Lisbon is well-worth the extra costs for hotels, activities, and meals when you consider the great experience you'll have walking through the historic Alfama neighborhood to the Sao Jorge Castle and eating along Avenida de Liberdade.

Istanbul is a place where east meets the west and that's all too visible in the city's dining scene and historic attractions like the Hagia Sophia and Topkapi Palace. While a one or two-day free stopover with Turkish Airlines in Istanbul may not be enough time to see everything the city has to offer, it's a good start, especially with a one-night free hotel stay for Economy ticket holders and two free nights for Business Class travelers.

Porto is often overshadowed by Lisbon, but with TAP Portugal's free stopover program, you've got a great opportunity to see all this off-the-beat destination has to offer. Make sure you add things to your Porto stopover list like wine tasting, a beach escapade, and a tour of the Palacio de Bolsa.

Enjoy views of mountains and a great artist scene in Vancouver with Air Canada's free one-night stopover program. Dive into the art scene at the Vancouver Art Gallery then hop on an Aquabus water ferry and head to Granville Island to get a taste of the diverse dining scene and shop among First Nations artisans. Don't miss out on a chance to walk the Capilano Suspension Bridge 230 feet above the Capilano River.

Travelers flying through Belgrade from John F. Kennedy International Airport with an eight to 24-hour layover can take advantage of a one-night stopover with Air Serbia. It includes free hotel accommodations and roundtrip transfers. While there, visitors should explore the Belgrade Fortress and have a traditional Serbian meal in the historic bohemian quarter, Skadarlija. At night, don't miss a chance to hit Belgrade's famous nightlife scene by visiting the splavs, or floating clubs.

Air Astana's stopover package in Astana, Kazakhstan, offers a one-night stay and transit from the airport for just $1. That's a pretty sweet deal that provides travelers with enough time to see the pyramid-like architecture of the Palace of Peace and Reconciliation or the golden domes of Nur-Astana Mosque. Don't miss out on shopping or visiting the indoor beach resort at Khan Shatyr Entertainment Center.

Sixty dollars seems like a reasonable fee if it means you can stopover in Honolulu on a long flight between the U.S. and Asia. During your stopover, soak up sun on the beach, hike the volcanic Diamond Head, and go back in time at Pearl Harbor. Just call Hawaiian Airlines to set up your stopover.

Admire Van Gogh's work or stroll along the canals of Amsterdam with KLM's free stopover program that allows for a free stay inbound and outbound. Travelers may have to pay additional airport taxes, but it'll be worth it to explore this historic Dutch city that's home to the Anne Frank House.

Seafood, beach-time, and nature hikes can be yours with a Panama City stopover with Copa Airlines and Copa Airlines Colombia. Travelers can cruise down the famous canal or take a quick day trip to hike through the nearby jungles. For something more culturally-focused, check out the UNESCO Casco Viejo neighborhood.

Ethiopan Airlines just rolled out a stopover package in August 2018 to promote tourism in Addis Ababa. The different packages are hosted by Ethiopian Holidays which offer a range of tourist experiences that include visiting the obelisks of Axum, the medieval churches of Lalibela, the source of the Blue Nile, coffee tours at Kaffa, and the castles of Gondar.

Brussels Airlines offers travelers up to five nights with their free stopover program in Brussels. Travelers also get to choose two cities where they can take advantage of free entry to museums and historical sites. All Belgium cities are within an hour of each other by train, so it's fairly easy to see a lot of this country with a Brussels Airlines stopover.