Before World War 2 the Baltics had a substantial German population. Germany proper extended all the way to East Prussia with its capital Königsberg. But many Germans also settled further North in the Baltic states. Indeed, most places in the Baltics also have historic German names (e.g. Reval for Tallinn). And plenty of historic figures were of German ancestry. Take our beloved Struve Arcs. Struve was German and taught at was then a German university in Tartu/Dorpat.
As such, travelling the area you will meet plenty of Germans trying to connect to their ancestors. The Curonian Split features quite heavily in these itineraries as it was a prime travel destination of the locals; and still is.
The Split itself is arguably man made. The Prussians intervened to stabilize the dunes and protect it against the sea. It is this engineering feat for which the site was inscribed. Personally, I enjoyed hiking the woods, the beeches and the dunes, but felt a bit hard pressed to pin point the OUV.
Apart from the beeches Nida nowadays boasts two main attractions:
The old wooden tourist houses in the city center. The most prominent one used to belong to Thomas Mann.
The big Parnidis dune South of the city.
Getting There and Around
Thanks to Air Baltic plenty of locations in the Baltics are within reach and budget. Only caveat is that you will have to transfer at Riga. I flew via Riga to Palanga and took a bus to Klaipeda from there. The next day I took a morning bus from Klaipeda to Nida on the Curonian Split.
I mostly stayed in and around Nida. I later learnt that you can do one way bike rentals to ride along the coast. The Curonian Split is too long to do it simply by walking.
Getting to the Russian side meanwhile entails getting a visa. Looking across the border it seemed to be the far quieter side.
While You Are There
Klaipeda (German Memel) used to be the Northern most German city and part of the Hanseatic League. Most of the old town was destroyed during World War 2. You can still find glimpses. Due to the German heritage you will meet plenty of German tour groups, primarily consisting of retirees.