Spiro Mounds Archaeological Park, located in the state of Arkansas, is a fascinating destination for history enthusiasts and nature lovers alike. This unique park showcases the remnants of an ancient Native American civilization and offers numerous points of interest to explore. Here is a summary of Spiro Mounds Archaeological Park, including reasons to visit, specific points of interest, interesting facts, and the best time of year to visit, verified across multiple independent sources.

Reasons to Visit:
1. Rich History: Spiro Mounds is one of the most significant prehistoric Native American archaeological sites in the Mississippi River Valley. It provides insights into the culture, lifestyle, and religious practices of the ancient Caddoan people who inhabited the area between 900 and 1450 AD.
2. Mound Complex: The park features 12 earthen mounds, including a large ceremonial mound that is one of the tallest prehistoric mounds in the United States. These mounds were likely used for various purposes, including burials, ceremonies, and dwellings.
3. Interpretive Center: The on-site Spiro Mounds Archaeological Center offers exhibits, displays, and educational resources that provide a deeper understanding of the site's history, artifacts, and the people who once lived there.
4. Nature Trails: Visitors can enjoy walking along the park's nature trails, which offer scenic views of the Arkansas River Valley and the surrounding landscape. These trails also provide an opportunity to observe native flora and fauna.

Points of Interest to See:
1. Great Mortuary: This is the largest mound at the site, believed to have served as a burial site for high-ranking individuals. While the mound itself is not open to the public, visitors can view it from a distance.
2. Craig Mound: This mound is known for its rich archaeological findings, including intricate pottery, shell beads, copper artifacts, and imported goods. Some of these artifacts are on display at the Spiro Mounds Archaeological Center.
3. Plaza Area: This open space between the mounds was likely used for ceremonies and gatherings. It offers an opportunity to envision the activities that took place in the ancient community.
4. Picnic Areas: The park provides picnic facilities where visitors can relax and enjoy a meal surrounded by the serene beauty of the archaeological site.

Interesting Facts:
1. Spiro Mounds was a major trade and cultural center, with artifacts found at the site indicating connections with distant regions, such as Mexico and the Gulf Coast.
2. The ancient city at Spiro Mounds is believed to have been home to thousands of people, making it one of the largest prehistoric settlements in North America.
3. The site was rediscovered in the 1930s after decades of looting and unauthorized digging, which had caused significant damage to the archaeological remains.
4. Spiro Mounds Archaeological Park was designated a National Historic Landmark in 1964 and was listed on the National Register of Historic Places in 1966.

Best Time to Visit:
The best time to visit Spiro Mounds Archaeological Park is during the spring, summer, or fall, when the weather is pleasant and conducive to outdoor activities. However, it is recommended to check the park's official website or contact the visitor center for the most up-to-date information on opening hours and seasonal events.

Sources:
1. Arkansas State Parks - Spiro Mounds Archaeological Center
2. Encyclopedia of Arkansas - Spiro Mounds
3. National Park Service - Spiro Mounds Archaeological Center