“To put a girdle round about the world.”

St. 3
Dover Beach (1867)

Part II, line 194
Pleasures of Hope (1799)

Kubla Khan (1797 or 1798)

Table-Talk (1857)
Context: Round about what is, lies a whole mysterious world of might be, — a psychological romance of possibilities and things that do not happen. By going out a few minutes sooner or later, by stopping to speak with a friend at a corner, by meeting this man or that, or by turning down this street instead of the other, we may let slip some great occasion of good, or avoid some impending evil, by which the whole current of our lives would have been changed. There is no possible solution to the dark enigma but the one word, "Providence".

Theodric : A Domestic Tale; and Other Poems (1825), To the Rainbow
Context: p>How glorious is thy girdle cast
O'er mountain, tower, and town,
Or mirror'd in the ocean vast,
A thousand fathoms down! As fresh in yon horizon dark,
As young thy beauties seem,
As when the eagle from the ark
First sported in thy beam.For, faithful to its sacred page,
Heaven still rebuilds thy span,
Nor lets the type grow pale with age
That first spoke peace to man.</p

7-Jan-2006, DCFC website
You're just going to have to work that one out for yourself.