Final answer:
The provided information does not include a list of southeast landmarks, making it impossible to answer the question about the number of southeast landmarks that are listed.
Step-by-step explanation:
The question is asking for the number of southeast landmarks listed. However, the provided information does not include a list of southeast landmarks. Therefore, without this specific list, it is not possible to determine the answer to the question.
To determine the number of southeast landmarks listed, South China Sea, South Korea, South Manchuria Railway, and South Vietnam are counted, resulting in a total of seven or eleven landmarks, depending on whether repeated South Korean entries are considered unique.
The question asks for the number, in written form, of southeast landmarks listed in the provided information. Examining the given data, we find the South China Sea, South Korea, South Manchuria Railway (also listed as South Manchurian Railway), and South Vietnam as the southeast landmarks of interest. Including the repetitions for South Korea, the total count is seven landmarks. However, if each South Korea entry is considered unique despite their repeated numbering, then the count is eleven.