Well that and mountains, a lot of the Swedish-Norwegian border is made up of mountains making it very hard to invade

Pretty darn cool, you can definitely tell the difference in the seas of how well it survived in the waters.

We raised the Vasa out of the Baltic Sea which isn't quite salty or quite fresh water (aka brackish water). Meaning that there are less creatures able to break it down living in the waters which is why it survived relatively intact.

Even we here in Sweden have raised a pretty darn big ship from the 1600s and have since put it on display in a museum.

We did that in the 60s, it ain't exactly a huge innovation to be able to do so

Firstly it's worth noting that Swedish doesn't have umlauts like that and it's a separate letter completely. But disregarding the semantics we have officially used Ä and Ö instead of Æ and Ø since at the very least 1541.

Which is when Gustav Vasa's Bible was written that set new standards for the Swedish language, and the change to Ä and Ö was partly motivated by seeking a stronger separate identity from the Kalmar union (which was a Union between Norway Sweden and Denmark that we had just fought ourselves free from due to the Danes effectively controlling it).