From the outside, it appears to be a deft re-creation of some London landmarks, including a perfectly replicated King’s Cross Station and some townhouses that would fool a lifetime resident of Bloomsbury (keep an eye on the curtains in the second balcony window of 12 Grimmauld Place, the shabby townhouse). You have a re-created “Eros” fountain from Piccadilly Circus (unlike the original, this one actually has flowing water), cab shelters selling Britannia souvenirs and jumbo hot dogs, and a three-level-tall Knight Bus. If its conductor is there, have a chat with him, but don’t be alarmed if the shrunken Jamaican head hanging above his steering wheel butts into the conversation.

Hidden behind the London facade, through some sidelong brick portals, is one of the best theme park experiences in the world: essentially a wholesale construction of 3 city blocks around Diagon Alley, where wizards go for their provisions. It’s not so much a single attraction as it is a cluttered streetscape of shops, beverage and dessert stores, and painstaking design work that seals you off from the outside world. There are few right angles, but plenty of opportunities to spend lots and lots of cash. You could pass hours simply exploring details, from animated window displays (the skeleton that imitates your movements from the window of Dystyl Phaelanges is a standout) to clever signage larded with inside jokes (“These Premises to Let: Reptiles/Arachnids Allowed”). Click here for a photo tour of some of the best insider secrets hidden around Diagon Alley. 

The main thoroughfare is Diagon Alley, lined with the Leaky Cauldron restaurant and shops for wands, toys, and clothing. It leads dramatically to Gringotts Bank, which is crested by a petrified dragon that belches fire every few minutes (it gurgles right before). Gringotts is at the end of Horizont Alley, a 2-block lane noted for its pet store, beer hall, and ice-cream shop. On the left, it leads into Knockturn Alley, a fascinating indoor area that simulates a shady ghetto at night, right down to shifting clouds overhead and a tattoo parlor, Marcus Scarr’s, where animated sample designs writhe on the wall (do peek in).

Branching off from Diagon Alley on the right, you find Carkitt Market, a covered area recalling London’s Leadenhall Market, where the principal show stage is located. Performances include The Singing Sorceress: Celestina Warbeck and the Banshees (a talented but somewhat out-of-theme singer—J.K. Rowling’s favorite “offstage” character mentioned but not seen in the book series—rendering such classics as “A Cauldron Full of Hot, Strong Love”) and The Tales of Beedle the Bard (a street performance with puppets of two tales from the Potter spin-off book).

Nearly everything there is to do and taste comes with a price tag, and you can’t get these experiences outside Universal’s gates. It’s extraordinarily easy to get swept along in the merchandising mesmerization. (Click here for a photo roundup of some of the best things to buy at Diagon Alley.) Some of the best bespoke purchasing potential includes these Potterized twists:

* Gringotts Money Exchange, Carkitt Market. Trade in “muggle money” (U.S. $10s and $20s only) for Gringotts Bank Rune Credit, a currency that you can use in both parks or, Universal hopes, take home as a souvenir (pure profit for the park). You can observe the crusty goblin teller without paying.

* Ollivanders, Diagon Alley: In addition to the same wand-selecting mini-show available at Hogsmeade, you may purchase a $55 interactive wand used to activate more than a dozen tricks wherever you see a medallion embedded in the ground here or in Hogsmeade. Stand on it, emulate the wand motion depicted on it, and you’ll make toilets flush, suits of armor animate, fountains squirt, and so on. It’s fun.

* The Hopping Pot, Carkitt Market, and the Fountain of Fair Fortune, Horizont Alley. Sip sweet concoctions for $5 each: Otter’s Fizzy Orange Juice, Tongue Tying Lemon Squash, Peachtree Fizzing Tea, and Fishy Green Ale with “fish eggs” (actually blueberry boba) on the bottom. They also sell the classic Potter potable, Butterbeer (in a mug made for Diagon Alley, $14; $8 in a plain cup), and two beers unique to the park, Wizards Brew (a chocolatey stout) and Dragon Scale (a light lager), both $10.

* Florean Fortescue’s Ice Cream Parlour, Diagon Alley. Try a range of only-here flavors including Chocolate Chili, Clotted Cream, Earl Grey and Lavender, and a dangerously addictive soft-serve version of Butterbeer ($8). Too busy? You can get Butterbeer ice cream next door at the Fountain of Fair Fortune, too.

* Eternelle’s Elixir of Refreshment, Carkitt Market. Mix your choice of $4.25 “elixirs” (Draught of Peace, Fire Protection Potion, and so forth) with $5 “Gillywater” (water) and something magical happens: Universal makes $9 on sugar water. (By the way, bottled water outside Diagon Alley is lower priced.)

* Weasleys’ Wizard Wheezes, Diagon Alley. The toy shop sells $11–$35 Pygmy Puff stuffed animals and a dazzling variety of novelty gifts. Buy the candies Ron ate to get out of school: Puking Pastilles, Fainting Fancies, Fever Fudge, and Nosebleed Nougat ($7 each). Attached is Sugarplum’s, stocked with more fanciful sweets (chocolate frogs!, $13), but the pickings are better over at Hogsmeade.

* Magical Menagerie, Horizont Alley. Where windows are filled with animated pets such as pythons and giant snails, procure specialty animal souvenirs such as plush and puppet versions of Fluffy, Hedwig, griffins, huge purple toads, and Hermione’s half-Kneazle cat Crookshanks ($25–$35).

* Borgin and Burkes, Knockturn Alley. Items from the darker arts, including plenty of decorative skulls. Something’s trying to escape the trunk by the wall.

* Shutterbutton’s, Carkitt Market. Via a green screen, put your family in the middle of a 3- to 4-minute, 12-scene DVD/download ($70), like a moving postcard exploring the Potter universe.