On the postcard's background is the map of Brussels Metro, which covers a total of 40 km, and consists of four conventional lines (M1, M2, M5, and M6) and three premetro lines. It dates back to 1976, but underground lines known as premetro have been serviced by tramways since 1968. Over the map are overlapped five representative pictures for the capital of Belgium. I don't know if they are placed correctly on the map or unrelated to it.
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