What are the ways to acquire and change territory?

What are the ways to acquire and change territory? Introduction is as follows:

I. Ways of territorial acquisition and change in traditional international law Countries acquire new territories through preemption, prescription, cession, conquest and attachment, which are theoretically called "five ways of territorial acquisition" in traditional international law. Preemption means "effective possession" of "ownerless land" Prescription is a long-term actual occupation of the territory of other countries. The cessation is the transfer of part of the territory according to the treaty. Conquest is the territory acquired by the enemy after being destroyed in the war. Attachment is due to natural phenomena or artificial methods to increase the site. ?

From the perspective of modern international law, prescription and conquest are based on the premise of invading the territory of other countries, which violates the principle of inviolability of anti-state territory; International law does not allow cession according to unequal treaties. The legitimacy of these five ways of acquisition should depend on whether they conform to the basic principles of modern international law. ?

Second, the new way of territorial acquisition and change in modern international law 1, referendum. Referendum, also known as referendum, refers to the full and independent participation of residents in a certain territory to decide the ownership of the territory. 2. Restore territorial sovereignty. The restoration of territorial sovereignty refers to the recovery of the territory illegally occupied by other countries and the restoration of the historical rights of the country to the relevant territories. For example, the return of Hong Kong.

What is the accepted standard of the legitimacy of a region ruled by a regime? ?

This is an international issue. The so-called subject of international law refers to the participants in international legal relations who have the ability to enjoy rights and assume obligations in international law, or called international legal personality. The subjects of international law mainly include countries and international organizations.