Recently I got into a conversation about the most "Romantic" works of art and people immediately quote works form the Romantic period. Romantic period in my view was lot more about the ideas, and imagery to depict the emotions that go with them. It was after all a time for change and new ideas. But I doubt if the most Romantic paintings came form that time. Firstly, the answer depends on what the concept of "Romantic" work is. To me it is as much to do with mystery and contemplation as it is to do with ideas and idealism. Works during the romantic period were too defined, not leaving enough to imagination. Having said that I think the most "Romantic" piece of art, ever, comes from that period which is
"Wanderer above the Sea of Fog" - Caspar Friedrich
This is in Kunsthalle museum in Hamburg and you can stare at this forever!
However, for me impressionist age is perhaps the most "Romantic" period. There is mystique and complexity in the works that make it more appealing to me. See a few works below and decide for yourself
Other works from Romantic period
Liberty leading the people - Eugène Delacroix
More typical work from the period
The Fighting Temeraire tugged to her last berth to be broken up - JMW turner
Not so typical work of the period
Works from Impressionist era
Cliffs at Etretat - Claude Monet
Woman with a Parasol - Claude Monet
Dance at Le Moulin de la Galette - Renoir
Starry nights - Van Gogh
View of the Saint-Martin Canal - Alfred Sisley