Poems employing the circular structure begin in one place, then journey away from that place, only to (as you may have guessed) circle back to the beginning. Here are a few examples:
“Instruction Manual,” by John Ashbery
“every lake…,” by Charles Bernstein
“Man on a Fire Escape,” by Edward Hirsch (in Earthly Measures: Poems (New York: Knopf, 1994).
“I Loved My Friend,” by Langston Hughes
“The Opposite of Crunchberries,” by Jennifer L. Knox (in A Gringo Like Me: Poems (Soft Skull, 2005)).
“O, She Says,” by Hailey Leithauser
“New Heavens for Old,” by Amy Lowell
“You, Andrew Marvell,” by Archibald MacLeish
“Natural Selection,” by Alan Shapiro
“On Gravity,” by Mary Szybist (in Granted (Farmington, ME: Alice James Books, 2003): 39).
“A Quiet Life,” by Baron Wormser
Because its first and third lines return in its final quatrain, the pantoum form also features the structure of a circular movement. Check some out:
And, of course, the circular structure is popular in arts other than poetry. Check out some of these examples:
Structure & Surprise 
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[…] are many more circle poems (try Michael Theune’s excellent website for a start) but the rain has eased and it’s time to write […]