Every single square inch of dry surface land on Earth has been claimed or owned by either an individual, corporation, or government. What was the last time and place where land was unclaimed and unowned? Or does any still exist?
Hi, yes, unclaimed/contested land does still exist. Whether you could just show up and start building a house there is another question. There have been scattered answers to this question in several threads; you can get started on these
Why is there no unclaimed land (Exempting Antarctica) any more and when did it become unacceptable to just have areas independent of a national entity? - /u/MYGODWHATHAVEIDONE gives a geopolitical introduction
When was the last time that a piece of land on Earth was not claimed by a country? - thread discusses Bir Tawil, the Antarctic, and the Croatia-Serbia border
Excluding Antarctica, what was the last piece of land to be claimed by any nation? - a chatty thread that mentions Bir Tawil, and notes several of the most recently-claimed regions