Meetings in buildings

Sometimes, meetings take you to weird places. I had no idea that Century City's new building right across the Twin Tower, 2000 Avenue of the Stars actually has a huge hole in it. What seems like the architecture style of the second, judging by the CCTV building in China, this is actually fairly cool. Of course being in earthquake world, This building can go very tall. For the price of the gaping hole, how much office space got displaced, and how much more are they charging as a result? Either way, the Twin Tower complex in LA, isn't the spectacle of other cities, but it's neat for a second.

The buildings are still there, and I guess there's not much you can do them, except work the area around them. When is the last time a packed urban high rise building (not hotel) got demolished on purpose? I'm not talking about World Trade Building 7, but literally a public demo of a gigantic building? No remodels seem possible, so I guess they stand until they can't anymore. I wonder how long a tall building like this lasts?