20190714_133717 A narrow curving street in Vilnius Old Town
20190712_141351 A dune as seen from a boat cruise
This could be the Parnidis Dune / Parnidžio kopa -- the biggest dune in the Curonian Spit (at least the Lithuanian part of it) or its neighbor the Great Dune, a.k.a. The Dune of Gliders ("Sklandytojų kopa"). It was named after a gliding school that used to exist there in 1930s, during Lithuania's first period of independence. The Great Dune is the southernmost point in the Lithuanian part of the Curonian Spit, located right at the Lithuanian border with Russia. It used to be the tallest dune in the Curonian Spit, but lost some of its height due to erosion back in the day when people were allowed to climb on it. At its tallest, it measured 70 meters.
We saw these dunes while on an hour-long boat cruise from Nida.
There are many boat cruises out of the Nida harbor. Some are as short as an hour: they sail along the Curonian Spit up to the border with Russia, say hello to the Lithuanian coast guard ship patrolling the border, turn around and go back. Others are 4-5 hours long: they cross the Curonian Lagoon and visit interesting coastal towns on the continental side. Unfortunately, there is no way to find out in advance if a particular cruise that interests you will be sailing on a given day, because they only sail if they get enough customers. On the day we were in Nida, we were able to get on an hour-long cruise to the Russian border and back. It gives you a view of the biggest dunes of the Curonian Spit. A pre-recorded narrative tells you about the places you see in three languages -- Lithuanian, Russian and German. (There are lots of German vacationers in Nida.)