This is Meghan’s first view of Iron, from The Iron King:

A twisted landscape stretched out before us, barren and dark, the sky a sickly yellow-gray. Mountains of rubble dominated the land: ancient computers, rusty cars, televisions, dial-phones, radios, all piled into huge mounds that loomed over everything. Some of the piles were alight, burning with a thick, choking smog. A hot wind howled through the wasteland, stirring dust into glittering eddies, spinning the wheel of an ancient bicycle lying on a trash heap. Scraps of aluminum, old cans and foam cups rolled over the ground, and a sharp, coppery smell hung in the air, clogging the back of my throat. The trees here were sickly things, bent and withered. A few bore lightbulbs and batteries that hung like glittering fruit.

Here is Meghan’s first impression of Machina’s tower in The Iron King:

At last, the mountains of garbage fell away, and the lead packrat pointed a long finger down a barren plain. Across a cracked, gray plateau, spiderwebbed with lava and millions of blinking lights, a railroad stretched away into the distance. Hulking machines, like enormous iron beetles, sat beside it, snorting steam. And silhouetted against the sky, a jagged black tower stabbed up from the earth, wreathed in smog and billowing smoke.

Machina’s fortress.

As Meghan lies dying at the foot of Machina’s oak tree, her last act, the act that heals her and transforms her into the Iron Queen, is to infuse the combined powers of Summer and Iron into the land itself. Here it is, as described in The Iron Queen:

Movement swirled around me, flashes of color, showing a land both familiar and strange. Mountains of junk dominated the landscape, but moss and vines grew around them now, twisted and blooming with flowers. A huge city of stone and steel had both streetlamps and flowering trees lining the streets, and a fountain in the center square spouted clear water. A railroad cut through a grassy plain, where a huge silver oak loomed over crumbling ruins, shiny and metallic and alive.

“Summer and Iron,” Machina continued softly, “merged together, becoming one. You’ve done the impossible, Meghan Chase. The corruption of the Nevernever has been cleansed. The Iron fey now have a place to live without fearing the wrath of the other courts.”

More areas within the Iron Realm:

Machina’s Tower