Hiiumaa's Hill of Crosses is a small, poignant memorial tied to the island's Swedish community. The first cross recalls the Swedes forced from Hiiumaa in 1781 under Catherine II and sent toward what is now Ukraine; later visitors added their own crosses in remembrance of that difficult journey.
Do not expect the scale of Lithuania's famous Hill of Crosses. This is quieter and more local, worth stopping for if you are exploring the island by car and want a brief encounter with one of Hiiumaa's stranger historical layers.