The big enclosure

Caspar David Friedrich painted this hushed marshland along the Elbe River near Dresden late in his life, and the mood tells you as much. Most of the canvas belongs to the sky, glowing in bands of orange and gold that fade into deep blue as the sun goes down. Below stretches a wide expanse of muddy flats and shallow pools that hold the last bit of light, with a single small boat left stranded in the mire. As a leading figure of German Romanticism, Friedrich cared less about copying nature exactly and more about the feeling it gave him, and this scene carries a quiet, slightly lonely stillness.

The horizon here is worth a second look, curving gently as though the land itself is bending away from us. Some believe Friedrich shaped it this way to make us feel small against the sheer size of the world. Painted after he had suffered a stroke and was facing his own later years, the work is often seen as a meditation on time passing and things coming to an end. What might otherwise be an unremarkable patch of swamp, the sort of place you would walk past without noticing, becomes something oddly moving under his brush.