Nostalgia is a funny feeling. It is probably the best depiction of bittersweet that there is. Nostalgia can make people happy in the way it brings up fond memories and reminds people of better, easier days. Nostalgia can also be sad, though, because it comes with the harsh realization that those days are long gone, and times have changed drastically. Time is a weird concept, there is no stopping it, but everyone can learn to appreciate it.

While it may seem like a weird concept since the world is still in the 2000s, 2000s nostalgia is very real. Kids born in the year 2000 are 24 now, which means there are many things from their own childhoods that have changed dramatically over the past couple of decades. The 2000s have been a rollercoaster so far. Technology is everything, and it is everywhere. No one can escape its takeover; everyone is learning to live and utilize it. It is interesting to see just how much things have changed even since the early 2000s, which is not that long ago, relatively.

Take a look back at some of the things that started this century off on an interesting foot. Here are 25 images to remember and think about while realizing how quickly time goes by.