The building that collapsed in Lahore, Pakistan, and killed more than 20 people, was a factory. It's thought it was brought down by an exploding boiler.
The building that collapsed in Beirut killed at least 25 people. A couple of theories for its collapse:
Maybe cracks in the building were made worse by heavy rain. Or perhaps its foundations were weakened by nearby construction.
In any case, for the professionals, a building collapse is one of the worst things that can happen.
Cameron Sinclair is one of the founders of the non-profit group Architecture for Humanity. For him, what's scary is rarely the design of buildings, rather it's how those designs are constructed.
"The quality of construction is diminishing greatly," he said.
"There was a time when we as architects would deal with a whole system of master craftsmen who would be working on the finer details of a building. Now it's kind of like the McDonalds of building. It's a lot of cookie-cutter, dropped-in solutions that are done to maximize profit locally."
That may be true, but it doesn't account for the building stock the world already has.
The factory that collapsed in Pakistan was about 25 years old, and the Lebanese building dated from the 1920s.
In these cases it's more a matter of upkeep and regulation.
For instance, one commentator suggested that—in Beirut—the fact that old laws keep some rents very low means landlords don't spend money on standard safety inspections.
And it's problems with enforcing the rules that Christopher Gaffney thinks are to blame for the recent building collapses in Brazil.
In Rio de Janeiro a 20-storey building collapsed onto two smaller buildings, both of which also went down.
Gaffney is an architecture professor there, and he notes that Brazil has a long and proud tradition of structural engineering.
"So this was a bit of a surprise and it's turn into a tourist attraction of sorts. But in terms of a shock at the falling apart of public infrastructure, people were not terribly surprised."
Gaffney sees cracks not in Rio's buildings so much as in the city's civic infrastructure: no-one's stepping up to take the blame.
"The mayor doesn't want to take responsibility, the governor doesn't want to take responsibility, the engineering firms don't want to take it," he said.
"And so this is a concern of mine in general for the way that the World Cup is going to be run."
That's the soccer World Cup in 2014, a major event that's only going to increase the stress on Rio de Janeiro.
Rio's problems are big and systemic, and Gaffney doesn't see the city's leaders tackling them.
"When you have a bit event coming in, when you have these gross failures of public administration, you expose yourself to international coverage and you expose your weaknesses," he said.
Anywhere in the world, developing big systems takes a long time, whether it's building a culture of responsibility or a well-regulated inspection regime, or a seamless construction process.
Maybe, says Cameron Sinclair, at Architecture for Humanity, that's why it's easier to blame fate when things go wrong.
"When we assume it's a freak accident, we dismiss it and we just ignore it."