What journey left an impression on you and why?

What journey have you undertaken during your life that made some kind of an impression on you or created a specific memory that will stay with you for the rest of your life?

My answer would be a trip to a specific part of Scotland with my grandfather due to him loving going to the west coast. He absolutely insisted that we had to go and basically days after we went on this day trip he revealed he was ill and he died 2 months later (through something unrelated to his illness). The impression it left on me was it being the last real day out with him and it will stay with me the rest of my life.

So what journey made an impression, either happy or sad, on your life?