What would prevent me from creating my own nation?
<p>Somehow related, but different: <a href="https://law.stackexchange.com/questions/583/claiming-my-own-country">Claiming my own country</a></p>

<p>Is it "legal" to buy a piece of land and claim it to be another country than before(either inventing a new one or migrating it to an already existing one)?
According to international law, it is. That's exactly what happened to the Crimea island in the Ukraine(now Russia maybe?), right?</p>

<p>Organisations like the EU or the UNO are trying to enforce international law.
Their force in regions like the Ukraine is limited, but in western Europe, that wouldn't be a problem. So, if it's possible without the influence of these international institutions, trying this in an area with their influence would be easier, right?</p>

<p>A similar thing happened in Hamburg, Germany in 1993. But that was an <a href="http://www.netsamurai.de/netplanet-harburg/kunstpfad/kunstpfad-mitte-29.htm" rel="nofollow noreferrer">"artwork"</a> (article in german).</p>

<p>Short summary: <code>In 1993, Piet Trantel, an artist, claimed a ~10x10m piece of land as "Niemandes Land" ("nobodies land"). The land was owned by the city Hamburg, and the government accepted his claim as a piece of art.</code></p>

<p>There are certain requirements of Statehood according to the Montevideo Convention on Statehood of 1933, which is just a codification of international customary law:</p>

<ol>
<li>a permanent population; </li>
<li>a defined territory; </li>
<li>government; and </li>
<li>capacity to enter into relations with the other states.</li>
</ol>

<blockquote>
  <p>Is it "legal" to buy a piece of land and claim it to be another country than before(either inventing a new one or migrating it to an already existing one)? According to international law, it is.</p>
</blockquote>

<p>Sure. But just because you say something is the case, doesn't mean it is. <em>Always.</em> Sometimes it is. But for present purposes, let's say that if you found an uninhabited island and said that you were a country, that wouldn't be the case - nor if you bought it from a man living on it.</p>

<p>If you found some land that belonged to another country and decided to claim it as that of an existing country, then it would depend on the specific circumstances.</p>

<blockquote>
  <p>That's exactly what happened to the Krim island in the Ukraine(now Russia maybe?), right?</p>
</blockquote>

<p>I don't think so. As far as I know, the annexation of territory isn't considered sale. In any case, the ownership of this land is still under dispute.</p>

<blockquote>
  <p>So, if it's possible without the influence of these international institutions, trying this in an area with their influence would be easier, right?</p>
</blockquote>

<ul>
<li>If <em>trying this</em> means <em>declaring some land you have purchased to be a new sovereign state</em><br>
Nope. You probably still don't meet the requirements for statehood.</li>
<li>If <em>trying this</em> means <em>the acquisition of some land by an existing sovereign state</em><br>
Maybe. Probably not. The Montevideo Convention requires that statehood not be gained through force; while member states' interests may be greater where they are more invested, the requirements for acquisition of territory are the same no matter where you are.</li>
</ul>

<hr>

<blockquote>
  <p>What would prevent me from creating my own nation?</p>
</blockquote>

<p>Money, defensibility, recognition, the fact that you probably don't own any land that you "buy" (depending on the jurisdiction and real estate system), the fact that you generally <em>can't</em> unilaterally declare yourself a sovereign state.</p>

international