Crisis Core Final Fantasy VII: Reunion has plenty of missable Trophies/Achievements, especially throughout the main story. The Seven Wonders Expert is one such Trophy/Achievement in Chapter 8.
Learned about all of Nibelheim's Seven Wonders.
Once you reach Nibelheim in Chapter 8, you’ll find a boy in the town square that you can speak with. He’ll tell you about the many mysteries of Nibelheim and that the locals have taken to calling them the Seven Wonders. He’ll ask if Zack is interested in getting to the bottom of the mystery and you’ll need to solve all seven of them if you wish to get the Trophy/Achievement.
Seven Wonders #1
The clue for the first wonder is that sometimes, the town’s drinking water sometimes comes out red and wants to know the reason why. This is the simplest wonder out of the lot of them, simply head over to the water tower in the center of the square and interact with it. Zack will climb up the ladder and discover a red Materia sitting inside the water. This will unlock the Phoenix DMW Image and is missable if you don’t get it during this section so be sure to snag it.
Seven Wonders #2
You’ll need to head into the Inn first and go upstairs to find a painting of a girl in the room. Return to the boy to learn that sometimes, the girl disappears from the painting. Pay a visit to the room once more to see that the girl has indeed gone from the painting.
Keep passing through the screen downstairs and upstairs until you see the man start heading up the stairs. Follow him into the room and you’ll catch him in the act. It appears that the painting is double-sided to help him remember he’s stashed some Gil in the wall. For keeping quiet about it to his wife, he’ll hand over 2,000 Gil.
Seven Wonders #3
The clue for third Wonder is about on Mt. Nibel, the boy wants you to bring something back as proof. Head to Mt. Nibel by leaving the town and taking the northern exit out of the Outskirts. Once on Mt. Nibel, follow the path and continue on at the intersection and you’ll trigger a battle against three .
If you’ve not been doing a lot of optional Missions to get powerful, then make sure you take out the bombs in the following order: Right, Left, Middle. The goal is to defeat them before any can explode and you’ll obtain the . If you fail, you can just exit the area and return to try again.
Seven Wonders #4
The fourth Seven Wonder is perhaps the most challenging as you’ll need to solve the riddle of the Laughing Safe in the Shinra Manor. Every digit for the safe is random, and you can learn more about how to find each digit in our dedicated safe code page. Your reward for this Wonder is a Mastered Materia.
Seven Wonders #5
You’ll have to progress the story by speaking to Sephiroth in the Inn and play through the events at the Mako Reactor. You’ll be back at the Inn following this, as Sephiroth has been couped up in the basement of Shinra Manor for days.
Return to Shinra Manor and go down to the basement area from the hidden stairwell upstairs. Head to the upper corner of this first area (ignoring the ladder for now) and you’ll trigger a battle with a , defeat it to obtain the Coffin Key.
Make your way down the ladder now and enter the room to the southeast to find many coffins. Open the coffin on the right and you’ll discover a man is sleeping in one of these coffins. If you use the key on the wrong coffin, you’ll need to go and retrieve another one from the above.
Seven Wonders #6
Once you return to the boy to inform him about the previous wonder, you’ll learn the clue for the next, of which he has no inkling to what it could mean. You’ll need to progress the Chapter at this point until Nibelheim is burning and you find yourself outside the Inn.
The boy will be there, outside of a house on fire and tells you that his mother is trapped inside, on the second floor (where you can see the window). Choose to go inside and you’ll have one minute to navigate to that window, all the while the camera will focus on the house from the outside.
The goal here, then, is to run at a direction until you can’t move any further and gradually work Zack up to that window and interact with it. As a general rule, run up as far as you can, then to the right and up again where you’ll find you can run upstairs by going left. You’ll need to come back towards the screen now and eventually work your way around anti-clockwise to reach the window. Once you reach the mother, you will need to retrace your steps back down and out the house.
Seven Wonders #7
You’ll need to wait until Chapter 9 for the final Wonder, although it’s a simple one. As you leave the Shinra Manor with Cloud, you’ll get a mail from the Wonder Hunter which, if you’ve been making sure you get every mail, will be the last sender you need for the Mail Completionist Trophy/Achievement. The mail will mention that the boy and his mother has moved on from Nibelheim, but that he’s stashed something for you, calling it the final Wonder.
In the same area, head toward the eastern entrance back to Nibelheim and search near the fence in the corner there. You’ll nab a Materia and score the Seven Wonders Expert Trophy/Achievement in the process.