Effigy Mounds National Monument is a quiet space of contemplation in the northeast corner of Iowa, containing 207 mounds, 56 of them effigies in the shape of animals. They are among the tens of thousands of earth mounds that once dotted the Midwest, made by the people who lived here in the Upper Mississippi Valley, ancestors to today’s Ho-Chunk people, also known as the Winnebago. To visit any grave is a solemn practice. To visit these mounds is to be brought into the presence of an unseen force where the ground has literally been raised. Writer Terry Tempest Williams shares more.