An apartment typically has little or no outside access. A balcony can't replace a backyard, and a communal pool patio is not a beach or a pond in the woods. Satisfy your craving for nature by adorning the mantel with bits and pieces collected on your walks, at a florist's or in a green market. A real, or twisted-grapevine, bird's nest with turquoise heritage hen's eggs you have carefully blown out -- or a handful of tiny speckled quail eggs -- creates a focal point. Cluster a couple of birch bark candles to one side of the nest. On the other side, an empty quart milk bottle holding a bare forked branch, a few tall pheasant feathers and an equal number of dried cattails adds height and more natural textures without upstaging the delicate colored eggs.
Display underwater treasures above the fireplace on a mantel that's a day at the beach. Scatter some fine beach sand along a white mantel, and set a line of huge white conch shells across the entire expanse, alternating whorly exteriors with flamingo-colored interiors. Gather summers of beachcombing into a few large glass canisters crammed with every kind of small shell from those shoe boxes at the back of the closet. Rest a painted canvas seascape in the center of the mantel, against the chimney breast. White candles in tall glass hurricanes will send glimmers of light over the captured shells at night.
Hang a high-style Art Deco geometric mirror over the fireplace so it reflects the objects on the mantel and the careful arrangement in the rest of the room. Then mass a series of objects, all in the same arresting color, on the mantel shelf. A collection of contemporary hand-blown glass vases in hourglass, rocket, globe and zigzag shapes -- all in the identical intensity of tangerine, teal, dusky purple, or taxi-cab yellow -- are shiny eye-candy, doubled by the mirror. Tuck just a couple of dramatic black-and-white photographs at one end or another of the shelf for balance. The images might be from your latest family vacation, restored heritage shots of ancestors or art views of a favorite travel destination. Once in a while, but not too often, place a single bright gerbera daisy in one of the vases.
Paint the chimney breast and surrounding wall soft blush, apricot or gray; train one or more small ceiling-mounted galley spots on the mantel, and showcase your favorite rock artists in a revolving display. Line up vintage album covers along the mantle, leaning them against the wall at a good viewing angle. Add one or two framed concert posters to vary the height, and overlap the covers randomly -- the whole mantel should appear unstaged, almost as if the albums were tossed up there. Change the albums with the others from the bin in the closet often enough so the covers don't become so familiar that you no longer notice them.