Solve these clues to fill the grid.
- To march aggressively into another's territory by military force for the purposes of conquest
- 2 Across
- A submersible warship usually armed with torpedoes
- 5 Across
- The king of Castile and Aragon who ruled jointly with his wife Isabella
- 6 Across
- 28th President of the United States
- 9 Across
- A protective mask with a filter
- 11 Across
- European country whose capital is Berlin
- 12 Across
- Russian founder of the Bolsheviks and leader of the Russian Revolution and first head of the USSR
- 1 Down
- A friendly nation (plural)
- 3 Down
- A struggle between competing entities in which neither side is able to win
- 4 Down
- Ancient region and Roman province on the Iberian Peninsula
- 7 Down
- A written agreement between two states or sovereigns
- 8 Down
- Biggest country in the world by area
- 10 Down