Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Initial Situation
Come on, guys, let's found a new town!
Hey, hey, the gang's all here and we're going to start a new city where everyone will always be happy forever! We'll call it Macondo and it'll be fresh and clean and have none of the hang-ups and craziness of the place we left behind! Oh, but we'll also have no contact with the outside world.
Conflict
Oh, wait, the government knows we're here…
Macondo reaches out to the outside world, and the outside world reaches back. Now there's mail delivery and a new mayor, who brings with him death, disease, and an influx of people who haven't come because of some idealistic dream, but for more earthy and practical reasons. This can't end well.
Complication
The government is clearly corrupt. Maybe it should be brought down.
Colonel Aureliano Buendía goes off to fight the system, even as the system slowly absorbs and corrupts him. Back in Macondo, a new crop of Buendías have lost the dreams and hopes of their parents and are starting to focus their energies on selfish obsessions. None of this is helping.
Climax
Perhaps the town will be saved by the banana plantations! Oh wait, not so much.
The banana company creates prosperity for a while, until its workers strike for better employment conditions and are mercilessly gunned down. This scene of massacre is so awful and poignant that it definitely serves as the climax. As weird and terrible as the rest of the book's events are, this one takes the cake. Macondo, meanwhile, is in denial that any of this has happened.
Suspense
Will there ever be a generation of Buendía children that does better than their parents? Will Macondo ever return to the wonderful place it started out as?
Um, no. In fact, quite the opposite. Each successive generation of Buendías only repeats its parents' mistakes, with incest, sexual obsession, laziness, and a general incuriosity about the past dominating their personalities. Macondo goes through a destructive flood, loses many of its citizens, and is generally written off as a provincial backwater. Still, we hold out hope, wondering if maybe something will change.
Denouement
Amaranta Úrsula, the last hope of the Buendía family, will surely escape Macondo.
No, she won't. Instead, she comes back, ditches her husband, sinks into weird incest with her nephew Aureliano (II), and ends up giving birth to the deformed baby predicted at the beginning of the novel. This is the beginning of the end, and definitively answers our question from the suspense description.
Conclusion
Death and destruction for all.
Just like it sounds, everyone dies and Macondo is wiped off the face of the earth by a hurricane.