Buildings

Buildings are special units that are immune to most spells, use Fortified Armor, and are immobile. Destroying a Building rewards you with a bounty, similar to most Creeps or Heroes. However, some Buildings will also give a bounty to the entire team, rather than the destroying player. Buildings are divided into several categories, each with their own role.

Towers
Each faction's three lanes are guarded by 3 Towers, and their Ancient guarded by 2 neighboring Towers. Towers become higher tier depending on how far they are in a lane. Every Tower, except for Tier 1 Towers, is invulnerable until the Tower proceeding it is destroyed. The two Towers defending a team's Ancient become vulnerable if any Tier 3 Tower is destroyed. Note: No barracks have to be killed to make these towers vulnerable. Both of the Tier 4 Towers must be destroyed in order to remove the Ancient's invulnerability.

Towers in tiers 2, 3 and 4 have backdoor protection, which causes them to regenerate health at 90 hit points/second and take 25% damage from illusions if they are attacked without nearby creeps. If there are enemy creeps (or corpses) nearby, the backdoor protection is disabled and any damage dealt will not be regenerated. Backdoor protection will not regenerate damage dealt by friendly units.

All towers have a sight range of 1900/800, and an attack range of 700. All Towers deal Siege Damage, which deals only 75% damage to Heroes, but 150% damage to all siege Lane Creeps. Additionally, all towers have True Sight in a 900 area around them, allowing them to see any invisible units including Observer Wards and Sentry Wards.

Worth noting is that if an individual hero destroys a tower, his team actually gets less gold overall than if his faction (creeps) had destroyed the tower. However, the destroying hero gets more gold than normal. The average gold totals for a hero last hit are 1262/1471/1681/1891 versus 1575/1750/1925/2100 for a faction kill and 500/600/700/800 for a denied tower.

Ancients
Ancients are massive structures found inside each faction's base. In order to win, each team must destroy the enemy team's Ancient. Ancients have no offensive abilities themselves, but are guarded by 2 Towers. They cannot be attacked until both Towers are destroyed.

Ancients have 4250 hit points, and regenerate 3 hit points/second. Ancients also have 15 armor, 1800/1800 sight range, and True Sight in a 900 area around them.

Barracks
Barracks are special buildings, defended by Tier 3 Towers, that are responsible for keeping Lane Creeps as powerful as their counterparts. There are two Barracks for each lane per faction - one for Melee Creeps, and one for Ranged Creeps. Destroying either Barracks provides a large boost to the destroying team's associated Lane Creeps, increasing their statistics, as well as reducing the gold and experience they give when killed.

Barracks are invulnerable until the Tower that is guarding them is destroyed. Barracks all have 1500 hit points, and regenerate 2.5 hit points/second. Barracks also have 900/600 sight range and a bounty of 352-370 gold. Barracks do not have True Sight, but do have backdoor protection.

Fountains
Fountains are Buildings located in the respawn areas of both bases, and provide healing and mana regeneration to all allied units near it. They also attack any enemy unit that comes within 800 range, dealing 190-199 physical chaos damage per attack.

Mana and Health regeneration provided by the fountains is 4% maximum HP or Mana per second plus an additional 14 Mana points per second. It takes about 25 seconds to heal any hero from low health to full. Dropping items that provide Mana speeds up the process.

Bottles that are not full will be automatically refilled when you are near the fountain. Using Bottles while near the fountain speeds up the rate of regeneration, allowing Heroes to heal themselves and restore Mana faster.

Other Buildings
In addition to the above Buildings, there are other Buildings that act as buffers within a base. These Buildings have no effect on a team's outcome, other than providing a buffer for Lane Creeps to attack once they are inside of a base, and dropping a larger than normal gold bounty when destroyed.

Other Buildings have 500 health, 0 armor (fortified), and backdoor protection.

Glyph of Fortification
The Glyph of Fortification is an ability usable by any player on a team that renders all buildings owned by their team invulnerable for a short duration. It can only be used once every 5 minutes, and lasts for 4 seconds. Glyph can be used to stop enemy pushes, or slow them down long enough to organize a defense.