25 feet Sea Level Rise!

That's an extreme number and would require large-scale collapses of the Greenland Ice Sheet and/or the West Antarctic Ice Sheets. Nevertheless, it is instructive to see what such a rise in sea level would actually look like - here are two options:

• Nickolay Lamm (includes a good description how this was done)
• io9 (additional animated images such as the one below)

25 feet sea level rise from io9