Go to Town for the Red Coins
From the Super Mario Wiki, the Mario encyclopedia
Go to Town for Red Coins is the fifth mission of Wet-Dry World in Super Mario 64 and Super Mario 64 DS. The mission is renamed Go to Town for the Red Coins in the DS version to make it more grammatically correct. The mission's objective is to collect the Red Coins in the downtown area.
There are two ways to get to the downtown area. One way is making the water level rise as high as possible by jumping into the painting at its highest point; by doing this, the water level will be high enough to jump over the tall mesh fence in front of the player's starting position. Another way is to use the cannon on the opposite corner of the course and fire in through the top of the fence. In the DS version of the game, an additional way is available: Playing as Luigi, the player can use his Power Flower ability to phase through the fence. Once behind the fence, the player needs to swim down through the tunnel and into the downtown area.
Once in the downtown area, the player needs to swim directly downward and activate the Crystal Tap to lower the water. All of the Red Coins, aside from one, are in blocks the player has to break. Four of the Red Coins are in the central plaza, and the other four are on top of the buildings. To get to two of them on top of the buildings directly in front of the downtown's entrance, the player needs to use either Mario's wall jump or Luigi's backflip. The player can jump to the other rooftops from the plaza walls. Once all eight Red Coins are collected, the Power Star will appear at the Star Marker in the plaza.
Names in other languages