Part of the problem with sequels is that they are essentially continuations of stories that were never supposed to continue in the first place. Rather than being a planned expansion to an ongoing narrative, sequels have traditionally been given the green light after a movie has proven to be financially successful. Today, after the success of superhero movies, Lord of the Rings and the Harry Potter franchise it's much more common for genre films to have plans for sequels right from the start but there are still plenty of movies that try to keep the gravy train rolling despite not having many tracks laid ahead and frequently that leads to them going off the rails.
LIKE A TRAIN DO YOU UNDERSTAND
For this reason, it's important to have a few good stock sequel plots on hand that can be recycled again and again and one of the most popular is the 'fuck it, just do the first movie again but in a different city.' Just take the same script you had before, copy and paste in a few fish-out-of-water jokes and change the villains name to something more foreign and call it a day. To further the laziness of it, it seems there was some kind of international treaty signed long ago to ensure that it was always the same handful of locations visited for sequel. You're much more likely to see China, Japan, the all-encompassing vagueness of 'Africa'. Don't expect a Bridesmaids II: Ljubljana Lockdown any time soon. London, which is nice and exotic for Americans but still has plenty of white people speaking English, is a popular destination.
I'm honestly a little surprised that this one got the sequel and not the Foxx/Tatum one, as I thought the consensus was that White House Down was marginally better in being slightly more self aware or as self aware as a movie can be when it is directed by Roland Emmerich. However I looked it up and Olympus Has Fallen was able to make a better profit, by obvious virtue of having came out first so that by the time the other one came around people were convinced they'd seen it already. Don't be surpised if Emmerich very quickly commissions Downing Street Down or whatever, beating this sequel to the punch and do the same thing, forcing all of us into a never ending cycle of middling action movies where President Eckhart and President Foxx travel the globe and punch terrorists in the face. Taj Mahal Down, The Vatican Has Fallen, Belgium Down, At Least Half of the Pacific Islands Have Fallen and Samoa is Looking a Bit Wobbly and so on and so on long past the point where either of their characters could realistically have served terms, leading to the unspoken canon that they have both in their individual film worlds become savage dictators, punching all enslaved humans in the face and making quips about rocket launchers.