Ravine

 is an Expert Map in Bloons TD 6 added on Version 23.0 on February 2nd 2021.

Overview
The track takes the appearance of three bridges on what seems to link to Dark Castle.

There are two entrances on the track. Shortly after these entrances, the bloons' path is split into two divergent paths. On even-numbered rounds, the bloons enter via the left entrance. On odd-numbered rounds, the bloons enter via the right entrance.

The map is forested, with many trees blocking towers' line of sight. The sides of the bridges also block line of sight. Blocking elements cannot be removed.

The ravine itself is flooded with water. Water towers can be placed but will not have access to the track due to the steep ravine walls and the tall sides of the bridges.

Secret
Tapping the sword on the stone 24 times will fling the sword out. Starting from Version 24.0, if there are bloons on screen, the sword will fling onto the strongest bloon on screen, dealing three layers of damage onto up to 1 bloon. This is an important secret to make Ravine CHIMPS possible. This sword can damage any bloon type, including frozen(?), camo, lead, zebra, and purple. Note that this sword is one-use only.

Trivia

 * Ravine was not beaten in CHIMPS after the initial release of Version 23.0, as it is impossible to beat Round 7, with that round leaking a single Red Bloon at best. While there were successful attempts to complete Round 7, beating Round 6 and 7 in a single run is so far impossible. 24.0 changed the sword so that it now attacks one bloon when pulled, so that CHIMPS would become possible.
 * Ravine CHIMPS with Co-Op Starting Cash was achieved the second day after initial release of Version 23.0 by JustANormalSock. Link.
 * Ravine CHIMPS with 2 lives was achieved almost a week after initial release of Version 23.0 by Jajajosh. Link.
 * The first successful CHIMPS run on Ravine was completed on the first day of Version 24.0 by hanshubaby. Link
 * If the player taps the sword that sticks in the rock at the top of the screen 24 times, it will fly off screen. If there is a bloon, the sword will fly towards the bloon and pop it before doing so.
 * As featured in the solution for the 20th/21st February 2021 Advanced Challenge, there is a secret Sniper spot on this map that allows it to cover a substantial amount of vision along the left lanes.
 * This Advanced Challenge is the first one to feature this map, and has never featured in normal Daily Challenges (obviously because it's too difficult for the average player). The second Advanced Challenge to feature this map is 7th/8th May 2021's Advanced Challenge "Metallic Misery".
 * It is debatable whether Ravine is the new hardest Expert Map in BTD6, as the mid-game can be excelled with Neva-Miss + Alch buff, while the late-game is beatable with Etienne as the main firepower. Both reasons are that the track length is quite generous for Expert Map and that towers that ignore Line of Sight can excel the later rounds. However, for the early-game, it is among one of the hardest maps in the game, namely the complex pathing and heavy Line of Sight.
 * There is a bug where 0-4-2 Spike Storm and 0-5-2 Carpet of Spikes target the wrong lanes. Specifically, on odd rounds they will always target the front of the right entrance before the bend, while on even rounds they will not dispense storms of spikes at all. This was fixed on Version 24.0.
 * Submerge and Support can still de-camo bloons through bridge walls. The same applies for Bloontonium Reactor popping bloons through walls.