This is episode number seventeen, which is part of the series called Walk And Learn.Almost 90 percent of the world's tulip production is made in the Netherlands. The tulip, the national symbol of the Netherlands, was introduced to Western Europe through the Hortus Botanicus botanical garden in Leiden.Walking through the streets of this city dressed by centuries-old buildings, twenty-eight kilometers of waterways and eighty-eight bridges over its canals, I will explain the use of the most important prepositions of the Spanish language: por and para.It sounds cool huh? So join me!