Terrain Features:

Teleporting: By either standing inside the autoportal in their base and right-clicking the minimap, or using the teleport scroll item, heroes can initiate a 5 second channel which when complete will teleport them to any non-enemy tower. Teleporting to a neutral tower will send incoming-teleport pings to all players. Neutral towers cannot be destroyed.
Logs: These block pathing but not vision, allowing a hero on-lane to monitor nearby creep camps. Troops cannot see far enough to give vision of the camp.
Jungles: These areas containing the hostile camps are only readily accessible from the middle lane, or behind a tower on a side lane. They can also be accessed by teleporting to neutral towers, or cutting through the treeline. Only some heroes have abilities which can cut trees, which makes them an important asset to a team.
Kegs: These barrels explode when attacked, destroying nearby trees and causing a chain-reaction with other kegs. They can be used to open a temporary path from the jungle onto the side lanes, but because they're not visible from the side lanes they can't be used to enter the jungle.
Lightning Rod: Lightning Rods are powerup items which spawn every 3 minutes at either the top or bottom spawnpoint. A visual indicator appears 15 seconds before the item spawns to show at which spawnpoint it will appear. Lightning Rods cannot be picked up while there is an enemy hero within 500 radius of the rod. The item itself lasts for 99 seconds or one use, and allows the bearer to instantly teleport to any non-enemy tower without showing incoming-teleport pings to the enemy team.
Hostile Camps: Read more about them here.
Trees: Along with kegs, they respawn 60 seconds after being destroyed if no player-controlled units are near them. Many abilities can knock units into trees for bonus damage.