Well, through a mountain - Holy Cross Mountain in the Colorado Rockies.
The mountain is reached only with some difficulty, and in the early days of settlement of the Western United States the existence of a mountain emblazoned with a cross was legend. Eventually explorers documented the presence of the snow-crossed mountain made famous by an early photograph by William H. Jackson and later in paintings by Thomas Moran. The mountain itself became a popular tourist destination.
Longfellow had seen both Moran's painting and Jackson's photograph and some 18 years after the death of his wife, Frances (Fanny) by accidental fire, he penned The Cross of Snow in tribute to her. Longfellow had attempted to extinguish the flames of Frances' clothing which had ignited from a candle or spark from the fireplace without success. Longfellow's face was scarred and disfigured from burns he sustained during his rescue attempt. He stopped shaving after the burns healed and photographs taken after the tragic acccident show his prominent whiskers.
The Cross of Snow
In the long, sleepless watches of the night,
Looks at me from the wall, where round its head
The night-lamp casts a halo of pale light.
Here in this room she died, and soul more white
Never through martyrdom of fire was led
To its repose; nor can in books be read
The legend of a life more benedight.
There is a mountain in the distant West
That, sun-defying, in its deep ravines
Displays a cross of snow upon its side.
Such is the cross I wear upon my breast
These eighteen years, through all the changing scenes
And seasons, changeless since the day she died.