Note: Midgar and Gold Saucer have their own sections!

Ancient Forest
Utilizing the caprices of bugs and frogs, Cloud has to travel through this place to pick up one of his best weapons, the Apocalypse.

Bone Town
An undending expedition for buried treasure goes on here. You can find the Lunar Harp, as well as (later) the key to Midgar's Sector 5. The path north leads to the Sleeping Forest.

Cargo Ship
This ship heads from Junon to Costa del Sol. Cloud and party stow away here, wearing sailors' costumes, but Sephiroth makes a surprise appearance.

Chocobo Farm
Choco Bill, his son Choco Billy, and granddaughter Chole, take care of this spot. You can have four Chocobos in the pen and one in every stall you own. Bill will take care of selling the stalls, Billy sells Chocobo Lure materia and Greens, and Chole will tell you your Chocobos' stats and repeat the Chocobo Sage's obscure comments.

Chocobo Sage's House
The purple Chocobo Sage lives here and dispenses obscure advice, when he can remember it.

Coral Valley
Between the Sleeping Forest and the Forgotten City.

Corel Prison
This used to be Corel Town, before Shinra burned it down. Cloud ends up here after being framed by Dyne. This is a desert prison, seething with enemies, below the Gold Saucer. Dyne is the Boss of this place, and only with his OK can you win your freedom in a Chocobo race. Mr. Coates will grudgingly oblige you here, and Ester will help you through the race.

Cosmo Canyon
The original home of Red XIII. Bugenhagen lives in his observatory at the top of this native village. There's a secret door leading into the age-old Gi Cavern. The Gi tribe tried to invade Cosmo Canyon long ago, but Seto stopped them from getting anywhere. The Huge Materia you collect will be displayed in Bugenhagen's observatory later in the game.

Costa del Sol
A seaside paradise, Hojo takes some time off here basking in the sun. The only clue he can give you is to travel north to Mount Corel. You can buy a villa here if you've got tons of money to spare.

Edge
[AC] A city built up around the edge of Midgar. Tifa's new 7th Heaven Bar is located here.

[DoC] Vincent comes to Edge after reports of people disappearing, where he meets Shalua. The city's been largely evacuated, but Deepground apparently captured about 500 people. Rosso the Crimson dispatches an entire squad of WRO soldiers before Vincent confronts her, but at that point it's too late - the entire population has been sacrificed to Omega.

Forgotten City/Capital
A strange-looking place where the Ancients used to live, Aeris comes here alone to pray for Holy. The Forgotten Capital, underground, holds the water altar where she prays. However, coming here to look for her, Cloud is shocked when first he almost kills Aeris himself (the force of Sephiroth's will overpowering him) and then Sephiroth himself finishes the job. After her burial at sea, he continues the journey north to the Snow Fields to follow Sephiroth.
[AC] Kadaj, Loz, and Yazoo make this their headquarters; they bring the children of Edge here as part of their plan, and Cloud and Vincent battle them here.

Fort Condor
Shinra's after the Huge Materia stored in this tower, but rebels fight them every step of the way to save the almost-extinct giant condors in the tower. You can fight a nice mini-game here from time to time, and you have to in order to get one of the Huge Materia later in the game.

Gelnika
Shinra's secret helicopter-airship crashed and burned in the ocean. There are some ridiculously powerful monsters around, as well as some super items and materia.

Gold Saucer
Dio's masterpiece of entertainment. The currency here is GP instead of Gil, which can only be won in special ways. Here's the rundown:

Gongaga
A large reactor has melted down here, leading Scarlet and Tseng to check it out for Huge Materia (which it doesn't have). This is where Zack used to live.

Great Glacier
Cloud must use a map to navigate this huge wintry maze. Some nice items and the Alexander materia can be gained here. At the northernmost point, Holzoff gives some rest and advice for climbing up Mount Gaea.

Icicle Inn
This snowy town was the home of Dr. Gast and Ifalna before Hojo of Shinra invaded and stole Ifalna and her infant daughter, Aeris; and killed Gast. Cloud comes here looking for Sephiroth, but is detained by Elena and Shinra. He ends up snowboarding down to the Great Glacier!

Junon
A large port city, it has an upper and lower part. The lower part has only a few poor inhabitants (including Priscilla); the upper part, which can be reached via elevator, has many stores, bars, etc. There's also an Inner Junon which is manned by Shinra and operates the giant cannon mounted on the futuristic seaside section of Junon. Cloud travels here several times; to pose as a Shinra soldier and stow away on a cargo ship; to be sentenced to death by Shinra after Sephiroth calls Meteo; and to chase after the Huge Materia shipment in the Gelnika helicopter.

[DoC] Reeve mentions that 1200 people had gone missing in Junon (kidnapped by Deepground) before taking Vincent to Edge.

Kalm Town
This is where Cloud stops to tell everyone his history. The Mythril Mines and Chocobo Farm are nearby. Also, Elmyra takes Marlene here later, to escape Midgar.

[DoC] Vincent starts the game in Kalm, where Reeve has asked to meet him, but is interrupted by Deepground soldiers attacking the city and kidnapping civilians.

Materia Cave
There are four of these around the world, which require higher-level Chocobos to reach. They hold the HP<->MP, Mime, Quadra Magic, and Knights Of Round matera.

Midgar
A giant, sprawling night-encased city where you start off. Midgar is basically run by the Shinra corp. There are eight Mako generators spaced around the perimeter; the city is divided into eight sectors, and the Shinra headquarters is at the top of a giant "pizza" as Barret calls it - a huge steel disc covering the slums of the city. Here are the places you'll find in Midgar:

Mideel
A town with some nice shops, Cloud is washed up here with amnesia from the Lifestream and is taken care of in a clinic. However, the Ultima Weapon causes a rift in the Lifestream and Cloud and Tifa fall in! They wash up without harm, and with Cloud's memory intact.
[AC] Healin Lodge, where Rufus is recovering, is apparently doing nice business here.

Mount Corel
A mountain which leads to North Corel has a Mako Reactor at the center of it. This is the place where Barret and Dyne witnessed Corel's burning, and Dyne lost his arm.

Mount Gaea
A huge mountain leading to the Whirlwind Maze. You must keep warm on the way up!

Mythril Mine
The Midgar Zolom's swamp bars the way to this mine, which separates Midgar and Kalm Town from Junon. Only a Chocobo can cross the swamp fast enough to elude the Midgar Zolom. Sephiroth's left his calling card here - a giant Midgar Zolom impaled on one of his Masamune swords.

Nibelheim
The birthplace of Cloud and Tifa. Almost all of Cloud's memories are concentrated here, and Tifa must sift through them to find the real Cloud. There's an abandoned Shinra Mansion which also figures heavily here (Sephiroth went nuts in the library five years ago, and Vincent can be found there now.) The path leads north to the Nibelheim Mountains.

[DoC] Vincent explores Shinra Manor in an effort to find Lucrecia's forgotten thesis about Omega. He meets Rosso the Crimson here too.

Nibelheim Mountains
These craggy cliffs invented the word "foreboding". There's a Mako reactor nearby in which Hojo placed his experiments with Jenova breeding. Jenova herself is stored here, but Shinra extricates her to the Shinra HQ; Jenova was subsequently "rescued" from there by Sephiroth.

North Corel
An outpost built outside the old Corel Town, the survivors of Shinra's burning of Corel moved here and continued their mining operations. The only thing of note it has is a Ropeway Station to the Gold Saucer.

Northern Crater
The final dungeon leads straight into the world's core, where Holy is trying to escape, impeded by Sephiroth. The party must split into three to reach the inside of the Planet and the final showdown with Sephiroth.

Rocket Town
Cid lives here with Shera, his dismally abject servant, who is forever trying to make amends for a fault which cost Cid his dream. A large rocket, Shinra No.26, which went through a failed takeoff thanks to Shera, figures prominently in the background of the town. Palmer and Rufus make a scene here when trying to steal Cid's Tiny Bronco; he makes a daring getaway but the Bronco is grounded for good. Shinra No.26 is later revived for a desperate plan to destroy Meteor, and Cloud and company head up in it.

Sleeping Forest
North of Bone Town, the forest sleeps and doesn't let any traveler pass - until you can wake it with the Lunar Harp, which is buried in Bone Town. The Forest leads through the Coral Valley to the Forgotten City.

Snow Fields
North of the Forgotten City, it leads to Icicle Inn.

Temple Of The Ancients
This mysterious place is the resting spot of the Black Materia, which can call Meteor and is needed by Sephiroth. Aeris can speak to the spirits of the Cetra in here. Cait Sith heroically sacrifices his toy body to destroy the Temple and gain the Black Materia, but Sephiroth - or rather, one of the Sephiroth-clones - steals it anyway.

Underwater Reactor
The Huge Materia is being transported to the Shinra Sub in this subterranean Mako Reactor in Inner Junon. Cloud has to hijack his own sub and track it down!

Weapon Maker's Hut
He'll tell you about Dio and the Keystone. If you give him some Mythril, he'll give you Aeris's Great Gospel Limit Break.

Whirlwind Maze
The wound made by Jenova's falling is forever being healed by the Planet here, above the Northern Crater and the center of the Planet. Sephiroth finally gets a hold of the Black Materia here - thanks to Cloud! He calls Meteor and the world goes nuts.

WRO Headquarters
[DoC] Well... it's the WRO headquarters. It's attacked not once, but twice during the game.

Wutai
Yuffie lived in this very Japanese-looking (and sounding) town with her father Godo until his attitude drove her nuts and she left. Godo's mansion is still around here, and Yuffie knows the city like the back of her hand. You can visit the Pagoda Of Five Mighty Gods (where Yuffie can get the Leviathan materia if she defeats her father in battle) and Da-Chao Statue, where Don Corneo will later have a showdown with the Turks.