How do you write about something that was better than you expected, something that changed you in ways you can't even express? How do you describe the pain you felt, in your butt, in your heart, in your mind, biking up yet another hill, wondering if you could make it? 
Or the moment of absolute panic when you see your husband just ahead of you, flying through the air like a (very large) bird, over his handlebars and landing smack on his chest? (There's no picture of that because it all happened so quickly. Fortunately, he was fine and got back on his bike after about 15 minutes.)
Words cannot express the experience of sitting in the shade of a 12th century castle, looking over a gorgeous valley, eating a picnic lunch supplied by villagers all over the age of 70. 

How can you describe the Colleseum, the Forum and the Pantheon? What can you say when you walk on streets worn by the footsteps of millions of people and wonder if the apostles Peter and Paul walked on the same roads?
How do you talk about the 8 people, who you will likely never meet again, who were your constant companions, best friends and all around amazing people?
I find that words really cannot describe it all.