So his cross was chosen in honour of him (or for the saint's protection of the fleet or something like that). Since St. Andrew is the patron saint to the number of other countries (link) and associated with sea his cross may as well have been used on these countries' Navy flags. Estonia, however, is not on this list. read more
By understanding the Union Jack you can start to understand how the symbols for national identity are related throughout the world and why flags all over the world look so similar. This is the modern flag of the United Kingdom and it is actually a rather interesting study in the evolution of flags in Europe. read more
Senegal, flag of; Mali, flag ofEncyclopedia Britannica. These two flags share the same dimensions and basic green-yellow-red design of the vertical stripes, although there are slight shade differences in the colors. In addition, Senegal’s flag is distinguished by its green star in the central stripe. read more