Translation of usurp in Spanish

As it was the primary attraction for all tourist we were "escorted" by a few thousand other visitors. Our guide Samuel informed us about the ancient history of this special place.
We drove to the next spot exactly at noon. We were told that this spot would not be crowded at all during the lunch hour and we were not surprised to find it completely empty without anyone else.
Many thanks for your letter. I am delighted to tell you that I have passed my exams and am looking forward to the next year. Meanwhile I am planning a trip to Costa Rica and some places around there.