I can explain some of this
Greenland: The US has tried to purchase the island several times throughout history
Canada: US Americans have desired to take Canada since before independence from Britian. The original Articles of Confederation has a provision allowing Quebec to join the USA. Newfoundland had a small USA annexation movement before it became part of Canada
USA: All of the changes are/were proposed states, some had a real chance of happening (the break up of Texas) and others are just memes (The State of Jefferson in the west coast). Why chuds would want this, I don't know
Cuba: occupied twice by the US in the early 20th century
Dominican Republic: Then known as Santo Domingo, the US tried to annex the country in the 1870s but was shot down by congress
Mexico: Northern Mexico and Baja California were originally intended to be taken as US territory after the 1846 Invasion
Yucatan: White slavers in the briefly existing Republic of Yucatan once asked to become a US state
Nicaragua: On and off occupied and manipulate by the United States throughout history
Panama: Former US colony
Sicily: Occupied by the US in WW2. Post war there was a small sicilian independence movement, which included and even small movement to become a US state
Iceland: The US briefly considered purchasing Iceland after the US Civil War.
Faroe Islands(?): No clue
POB(?): Not sure what this is
South China Sea: Not sure what specific islands this is referring to
on Mars but we can't settle it?!!??! 
