(e.g. Turkey). Non-contiguous transcontinental states are those that have portions of territory that are separated from one another either by a significant body of water or by other land. Most non-contiguous transcontinental countries are countries with overseas territories. The boundaries between the continents can be vague and subject to interpretation, making it difficult to conclusively define what counts as a 'transcontinental state'. For the purposes of this article, a seven-continent model is assumed. Therefore, states that have territory across sub-continental boundaries, as well as plate boundaries that are only internal to continents, are excluded from this article. Some non-contiguous transcontinental states have territory situated on distant islands that may or may not be considered a part of another nearby continent (e.g. Yemen's Socotra and Portugal's Madeira). Though there is debate as to whether these states ought to be considered 'transcontinental', they are still included in this article. States that only have uninhabited island territory as a part of another continent (e.g., Venezuela's Aves Island) are considered transcontinental for the purpose of this article. While it is debatable as to whether states that have claimed territory within the Antarctic Treaty System can have actual control of that claimed territory (e.g., Chilean Antarctic Territory), they are included in this article. Some autonomous regions (or dependent territories) may be constitutionally distinguishable from the parent state that claims them as their territory (e.g., in the case of British Overseas Territories and the United Kingdom), thereby causing debate as to whether such states ought to be considered 'transcontinental'. They are nevertheless included in this article. Micronations, autonomous regions, and sub-national entities that are in themselves transcontinental are excluded from the lists in this article as a separate entry from their controlling state. Any entry must be a UN member state or a part of the United Nations System. Therefore, states with limited recognition are excluded from the lists in this article. Contiguous boundary Contiguous transcontinental states are those countries that have one continuous or immediately adjacent piece of territory that spans a continental boundary. More specifically, they contain a portion of their territory on one continent and a portion of their territory on another continent, while having these two portions connected via a natural geological land connection (e.g. Russia) or the two portions being immediately adjacent to one another (e.g. Turkey). Africa and Asia The modern convention for the land boundary between Asia and Africa