Museums are so underrated. No matter where your interests lie — be it science, music, history, or something else entirely — there's probably a museum dedicated to the subject. Perusing exhibits for a couple of hours is not only fun but educational, as well. The following eight museums are admission-free (some on select days only), so grab the family and enjoy an outing on the cheap.

Please note: Some or all of these museums may be temporarily closed or have altered hours due to COVID-19. Be sure to check before visiting.

1. Arizona Capitol Museum (Phoenix)

Located in the original Arizona State Capitol building, this tells the fascinating story of how State 48 came to be part of the Union. From hands-on activities for kids to more than 20 in-depth exhibits featuring historical artifacts, there's a little something to intrigue visitors of all ages. You can even enter the old chamber where the Arizona House of Representatives sat before relocating to a new building! Address: Address: 1700 West Washington Street, Phoenix, AZ 85007. More information here.

2. Southern Arizona Transportation Museum (Tucson)

Railroad enthusiasts, this one's for you. At the Southern Arizona Transportation Museum, you'll learn all about how the advent of the locomotive industry impacted Tucson. Exhibits are located both indoors and out and include model trains, works of living history, and even Steam Locomotive #1673, which starred in the film Oklahoma in 1955. Address: 414 North Toole Avenue,

Tucson, AZ 85701. Hours are 11 a.m. until 3 p.m. on Tuesday through Thursday and Sunday, and 10 a.m. until 4 p.m. Friday and Saturday. The gates to the steam train are open from 10 a.m. until 3 p.m. on Saturdays. More information here.

3. NAU Art Museum (Flagstaff)

NAU Art Museum, located on the Northern Arizona University campus, is committed to showcasing art beyond the aesthetic. Always seeking out new contemporary pieces to bolster its collection, the museum offers an educational experience sure to enrich your understanding of the arts. Look out for the ever-changing special exhibits! Address: Room M203 Building 10 Old Main, 620 South Knoles Drive, Flagstaff, Arizona 86011. More information here.

4. Yuma Proving Ground Heritage Center (Yuma)

Located in Building 2 on the Colonel George Howard Cantonment area at Yuma Proving Ground, this fascinating museum is the definition of a hidden gem. Spanning 14,000 square feet, the facility covers the YPG history from General George Patton's WWII training area to the present. With 14 exhibit galleries and a short film, you'll walk away with a bevy of newfound knowledge. Hours are 10 a.m. until 4 p.m. Tuesday through Friday. Address: Address: Unnamed Road, Yuma, AZ 85365. More information here.

5. Desert Botanical Garden (Phoenix)

Although not technically a museum, this list would feel incomplete without Desert Botanical Garden. The second Tuesday of every month is Community Day, which means admission is free for all age groups. Reserve your spot online and explore this 140-acre desert oasis on the cheap! Address: Address: 1201 North Galvin Parkway, Phoenix, AZ 85008. Hours are 8 a.m. until 8 p.m. More information here.

6. Center for Creative Photography (Tucson)

Tucked away on the University of Arizona campus, the Center for Creative Photography is a shutterbug's paradise. It was established in 1975 and has since accumulated the full archives of more than sixty of America's most famous photographers, including Edward Weston, Harry Callahan and Garry Winogrand. After visiting, you'll have a much better grasp of the history and evolution of photography. Address: 1030 North Olive Road, Tucson, AZ 85719. More information here.

7. Phoenix Sky Harbor Airport Museum (Phoenix)

You don't need to have a flight to catch in order to visit the Phoenix Sky Harbor International Airport. There's a museum inside the building that showcases Arizona's distinct artistic and cultural heritage with exhibits featuring art and information about aviation history. Address: 3400 East Sky Harbor Boulevard, Phoenix, AZ 85034. More information here.

8. Buddy Stubbs Harley Davidson Museum (Phoenix)

Are you a motorcycle fan? If so, you've gotta visit Buddy Stubbs Harley Davidson Museum. Peruse more than 100 rare bikes and related memorabilia, as well as exhibits detailing the history of motorcycles, in this 14,000 square-foot space. Address: 13850 North Cave Creek Road, Phoenix, AZ 85022. Hours are 11 a.m. until 5 p.m. Monday through Saturday, and 11 a.m. until 4 p.m. Sunday. More information here.

How many of these free museums have you visited? Did we miss your favorite spot? Let us know your thoughts in the comments section, and check out our previous article to learn more about Community Day at the Desert Botanical Garden.