SPIRO â On March 19, the Spiro Mounds Archaeological Center will host guided walks to share information about the spring equinox and how prehistoric people celebrated and dealt with the changes in the seasons. There will be walks at 11 a.m., 2 p.m. and 7 p.m. led by archaeologist Dennis Peterson. Each walk will take about two hours and require a mile of easy walking. Peterson will tell about this prehistoric American Indian mound site, the types of mounds, why they were created, and why some of the mounds are lined up for the sunsets of the solstices and equinoxes. He also will share the history of the excavations, Native ceremonies and stories, tales of the unusual happenings associated with the mounds and answer questions.