Question

say reson on the European countries felt the necessity of finding new trade route to Asia

Answer 1

the main reason is for European countries are interested in architecture .so, for this they have to travel for seeing different types of modified architecture style

Answer 2

hey..
may be this helps you.
here's your answer...
Before the voyages of exploration during this time period, Europeans had one option to get to the lucrative spice trade in the East—an overland route through what is now Russia and/or the Middle East.  After the fall of Constantinople in 1453, the Ottoman Turks charged Christian traders high fees to get through.  There were also marauding bands of Mongols and Tatars which regularly raided the trade caravans going through the Russian steppe.  After Vasco da Gama found a way to the Indian Ocean around the tip of Africa, European monarchs were happy that they could get in on the spice trade while cutting out these interlopers.  However, the trip was perilous given the weather conditions off the coast of Africa.  Many Europeans speculated that one could reach Asia more quickly by sailing west.  This led to further explorations by Columbus and the happy accident (at least for the Europeans) of discovering the Americas and the Caribbean.  

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