In Antarctica, there's something known as the Thwaites Glacier, though we'd rather use its far more impressive sounding nickname the 'Doomsday Glacier'.
The reason it has such a dramatic moniker is because it's part of what's been described as the 'weak underbelly' of the West Antarctic Ice Sheet, where it's vulnerable to collapse and if it goes it'll probably take the whole ice sheet with it.
This glacier and another one, called the Pine Island Glacier, are believed to be very likely to collapse without much warning in the future.
The consequences of this glacier's collapse could be a significant rise in sea levels, which would destroy many coastal towns and cities resulting in millions of people losing their homes.