With 120 Power Stars to find in Super Mario 64, some of them are a lot more hidden than others. This goes for both the castle secret stars and some of the main course stars found in normal levels.
One of the harder stars for Super Mario 64 newcomers to find is in Blast Away the Wall. This mission is the sixth mission in Whomp's Fortress, which can be unlocked after players obtain at least one Power Star.
In order to get this star, players will need to unlock access to the cannons located within Whomp's Fortress by talking to the Bom-omb Buddy located in the level. It is located at the edge of the shallow pool near one of the cannons.
The wall that players will need to launch Mario at is the wall on the right side of the large slope if players are looking at it from the bottom. However, launching Mario at the wall itself isn't enough. Players will need to hit the upper right corner of the wall in order to break it off. They can also use the cannon to destroy the corner of the wall to the left of the wall containing the star, but there is nothing inside for players to collect. There is no special markings indicating where Mario will need to hit, so players may want to aim for being at close to the corner as possible.
After hitting the wall, Mario will take a point of damage, so players aren't recommended to do this with low health. However, the Power Star will spawn after the wall has been broken off. To find the star, players will need to continue up the normal path to the top of Whomp's Fortress.
Once players get past the sleeping Piranha Plants, the Power Star will be located where the wall's corner was blasted away. Players can either use the cannon again to grab it with careful aim or they can walk on top of the wall and drop down onto it to collect it. After getting it, the mission will be over as well as the rest of Whomp's Fortress if players have already gotten the 100 Coin Star for this level.
This mission is later referenced in Super Mario Galaxy 2's Throwback Galaxy. In it, the galaxy is an entire recreation of Whomp's Fortress, but it already has the corner of the wall blasted off, showing that Mario had already collected the star there in Super Mario 64.
Super Mario 64 is now available as part of Super Mario 3D All-Stars, exclusively for the Nintendo Switch.