Because it gets dark very in most parts of Finland around Christmas (about 3.00pm) it's now traditional to go cemeteries and visit the graves of family members. Some cemeteries are enormous and police are on duty to manage the traffic, but everyone must walk the last few yards to the grave. Candles in hanging lanterns are left around the grave, often lots of many family members go. The whole cemetery is alight with glowing lanterns shining in the snow - a winter wonderland.
Other people like a sauna on Christmas Eve.