Tennyson

Tennyson's [1809-1892] poem "The Voyage of Maeldune" is a great, really interesting poem based on an ancient Irish Celtic legend. It's mythic, a symbolic look at Ireland's history and an adventure where they visit tons of odd, strange islands, like:

• The island of colorful birds singing like psalms
• The island with the psalm singing old man with noble monastic words
• The island with the golden wall around it
• The island with a woman pelting them with nuts
• The island with a river sky that was raining salmon
• The island on a pedestal

You can read the whole poem here, and here's an excerpt with great imagery:
The Voyage of Maeldune

[...]

V.

And we came to the Isle of Flowers: their breath met us out on the seas,

For the Spring and the middle Summer sat each on the lap of the breeze;

And the red passion-flower to the cliffs and the dark-blue clematis, clung,

And starr’d with a myriad blossom the long convolvulus hung;

And the topmost spire of the mountain was lilies in lieu of snow,

And the lilies like glaciers winded down, running out below

Thro’ the fire of the tulip and poppy, the blaze of gorse, and the blush

Of millions of roses that sprang without leaf or a thorn from the bush;

And the whole isle-side flashing down from the peak without ever a tree

Swept like a torrent of gems from the sky to the blue of the sea;