One of my favorite moments was a peaceful walk to see the Arenal Volcano. It is positioned in Costa Rica's fertile norther lowlands. It is a staple of the area - it's height is imposing. The volcano is in its resting phase at the moment and while you won't be able to watch explosions, I still recommend you make a point of going to Arenal.
The path to the viewing site leads through a lovely field - you will be surrounded by greenery and lovely touches of color as blooming flowers peak out from the dense forest. And then, a lovely view will open up - there will be immense clouds, open landscape, and in the midst of it your eyesight will be drawn to the Arenal Volcano.
So, when in Costa Rica, take a stroll to the Arenal Volcano as it will give you a sense of the present moment and magic travel brings about.