Krasnogruda Manor stands outside Sejny near the Lithuanian border, in a landscape of fields, woods, and small lakes. The estate belonged to the family of Nobel Prize-winning poet Czeslaw Milosz, and the restored manor now houses the International Centre for Dialogue.
It is the best short excursion from Sejny if you care about literature or the complicated identity of this corner of Europe. Check opening times before going, as tours and exhibitions can be seasonal.