pick something that your interested in, something your passionate about, music? art? video games? a film? if you choose a person try not to talk about thier education and when they were born etc, talk about why you like them and what they achieved, it its an artist, what the reasons or messages are behind thier work. dont be too complicated or complex, although your probably being marked on your knowledge if you go deeply into the physics of... i dont know, microwaves, people will get bired very quickly because they wont have any idea what your talking about!!!
Amelia Earhart. She is a very inspiring and interesting person to learn and talk about. I could go on and on about her achievement and her life as a young child from my memory.
I did a presentation on the history of the Interstate highway system... It was very interesting. Eisenhower first got the ieda from what he saw in Germany during WW2. Hitler built dual sided highways all across Germany for ease of troop transportation. The US was behind in this aspect.There were lots of men returning from WW2 who were unemployed. This project turned into lots of soldiers into workers who could be employed building roads. The congressional bill authorizing the freeway system in the US specified one thing specifically that the freeways would be for transporting a highly mobilized army. Technically in a time of war the US government could shut down all freeways to civilian traffic.
Think about it this way, before the Freeways, lots of cars very few good roads, after the freeways lots of good roads and people could get around very conveniently. People began to travel more as family, the concept of family vacation came of age. Trains dropped of as a means of log distance travel and goods transport. Over the road trucking became a staple means of transport. Motels sprung up by the tens of thousands, fast food chains became a booming business.
Small towns located on regular highways lost a big source of income. Freeways gave birth to suburbs. People could live outside the city and conveniently commute to work in the city.
The directions you could go with this topic are endless. You could close with something along the lines of stating that most of this major cultural change happened in the past 50 years.