Common buildings:
Picture
Name
Cost
Requires
Function
Village Hall
nothing
nothing
*The Village Hall is automatically built in every town and produces 500 gold per day.
Town Hall
2500 gold
*Village Hall
*Tavern
*The Town Hall replaces the Village Hall and produces 1000 gold per day.
City Hall
5000 gold
*Town Hall
*Blacksmith
*Mage Guild
*Marketplace
*This improvement upon the Town Hall produces 2000 gold per day.
Capitol
10000 gold
*City Hall
*Castle
*This final upgrade of the previous three buildings produces 4000 gold per day but can only be built in one of your towns.
*When you capture a town with a Capitol while you already have one, the new one is automatically downgraded to a City Hall.
Fort
5000 gold +20 wood +20 ore
*Village Hall
*When a Fort is built, the town is surrounded by walls.
Citadel
2500 gold +5 ore
*Fort
*This improvement upon the Fort adds a moat and an arrow tower to the town's defense.
*Creature growth increases by 50%.
Castle
5000 gold +10 wood +10 ore
*Citadel
*This final upgrade of the previous two buildings adds 2 smaller arrow towers to the town walls.
*The total basic creature growth is increased by 100%.
Mage Guild level 1
2000 gold +5 wood +5 ore
*Village Hall
*The Mage Guild allows heroes to learn 5 level 1 spells.
*Spellbooks can be purchased here for 500 gold.
*The Mage Guild also restores the full amount of spellpoints of any hero that ends his/her turn in that town.
Mage Guild level 2
1000 gold +5 wood +5 ore +4 crystal +4 gems +4 mercury +4 sulfur
*Mage Guild level 1
*This upgrade adds another level to the Mage Guild where heroes can learn 4 level 2 spells.
Mage Guild level 3
1000 gold +5 wood +5 ore +6 crystal +6 gems +6 mercury +6 sulfur
*Mage Guild level 2
*This upgrade adds another level to the Mage Guild where heroes can learn 3 level 3 spells.
Mage Guild level 4
1000 gold +5 wood +5 ore +8 crystal +8 gems +8 mercury +8 sulfur
*Mage Guild level 3
*This upgrade adds another level to the Mage Guild where heroes can learn 2 level 4 spells.
Mage Guild level 5
1000 gold +5 wood +5 ore +10 crystal +10 gems +10 mercury +10 sulfur
*Mage Guild level 4
*This upgrade adds another level to the Mage Guild where heroes can learn 1 level 5 spells.
Marketplace
500 gold +5 wood
*Village Hall
*The Marketplace allows you to trade one type of resources for another type. (the rate gets more profitable if you control more Marketplaces)
*You can donate resources to other players here too.
Tavern
500 gold +5 wood
*Village Hall
*In the tavern you can recruit new heroes for 2500 gold each. (the available heroes change every week)
*Your heroes that have fled or surrendered from combat end up in the tavern as well.
*In the tavern you can also listen to rumors.
*You can visit the Thieves' Guild to check on the status of your opponents. (the more taverns you own, the more detailed the information in the Thieves' Guild'll be)
*The tavern also increases the Morale of garissoned troops by 2.

Tower buildings:
Picture
Name
Cost
Requires
Function
Artifact Merchants
10000 gold
*Marketplace
*A set of artifacts is for sale here (you can use either gold or other resources to trade), and artifacts may be traded for resources too. (the rate gets more profitable if you control more Marketplaces)
Blacksmith
1000 gold +5 wood
*Village Hall
*The ammo cart can be purchased here.
Library
1500 gold +5 wood +5 ore +5 crystal +5 gems +5 mercury +5 sulfur
*Mage Guild
*When the library is built, one additional spell becomes available in each level of the Mage Guild.
Lookout Tower
1000 gold +5 wood
*Fort
*The Lookout Tower clears the fog around the town in a radius of 20 tiles. (this effect takes precedence of the fog created by the Cover of Darkness)
Sculptor's Wings
1000 gold
*Parapet
*4 more Stone Gargoyles/Obsidian Gargoyles are available each week.
Resource Silo
5000 gold +5 ore
*Marketplace
*Produces 1 gem each day.
Wall of Knowledge
1000 gold +5 ore
*Mage Guild
*Glyphs of Fear
*Visiting heroes permanently gain +1 Knowledge. (on their first visit only)


Tower creature buildings:
Picture
Name
Cost
Requires
Function
Workshop
300 gold +5 wood +5 ore
*Fort
*Gremlins are trained here.
Upgraded Workshop
1000
*Workshop
*Master Gremlins are trained here.
Parapet
1000 +10 ore
*Workshop
*Stone Gargoyles are trained here.
Upgraded Parapet
1000 +5 ore
*Parapet
*Obsidian Gargoyles are trained here.
Golem Factory
2000 +5 wood +5 ore
*Workshop
*Stone Golems are trained here.
Upgraded Golem Factory
2000 +5 wood +5 ore +5 mercury
*Golem Factory
*Iron Golems are trained here.
Mage Tower
2500 +5 wood +5 ore +5 crystal +5 gems +5 mercury +5 sulfur
*Parapet
*Mage Guild
*Magi are trained here.
Upgraded Mage Tower
2500 +5 wood
*Mage Tower
*Library
*Arch Magi are trained here.
Altar of Wishes
3000 +5 wood +5 ore +6 crystal +6 gems
*Mage Tower
*Genies are trained here.
Upgraded Altar of Wishes
2000 +5 wood
*Altar of Wishes
*Master Genies are trained here.
Golden Pavilion
4000 +5 wood +5 ore +2 crystal +2 gems +2 mercury +2 sulfur
*Mage Tower
*Nagas are trained here.
Upgraded Golden Pavilion
3000 +3 crystal +3 gems +3 mercury +3 sulfur
*Golden Pavilion
*Naga Queens are trained here.
Cloud Temple
5000 +10 wood +10 ore +10 gems
*Altar of Wishes
*Golden Pavilion
*Giants are trained here.
Upgraded Cloud Temple
25000 +5 wood +5 ore +30 gems
*Cloud Temple
*Titans are trained here.


The Grail:
Picture
Name
Cost
Requires
Function
Skyship
nothing
*Village Hall
*+5000 gold/day
*+50% creature growth
*Reveils the entire world map
*Defending heroes have their Knowledge increased by 15