Translation of lastly in Spanish

After this strange stop we moved on to the city center where he left me. I was on my own now and started to explore the little streets of the old center. It was packed with international visitors.
The climb was much exhausting than I had presumed. I had forgotten that we were at high altitude where there is less oxygen and that every step required double effort. It was a great exercise.
I boarded the AA flight to Cancun, and got there around two o'clock. It was my first time in Mexico. On the same night I had a flight booked to Havana, but I did not know whether I should take it.