1) The Eiffel Tower can be 15 cm taller during the summer due to thermal expansion.

2) The concept of sovereignty refers to the supreme authority and power of a state to govern itself, make decisions, and control its own territory without interference from external forces.

3) The word "forest" contains two vowels: O and E.

4) The concept of banking dates back thousands of years, with evidence of early banking activities found in ancient civilizations such as Mesopotamia and Egypt.