If you feel uneasy when browsing these pictures, don't worry. There's nothing wrong with you. In fact, Dr. Clay Routledge, who is a social psychologist and professor of Psychology at North Dakota State University, points out that we humans need meaning. So whenever there is a lack of it — as it seems with many of these images — we're triggered.

"According to terror management theory, a prominent theory in social psychology, humans are like all other animals in that we strive to survive. Our bodies consist of systems that work to keep us alive. And as conscious beings, we deliberately engage in efforts to avoid death. We are motivated to live. However, unlike other animals, humans are intelligent enough to realize that death is certain. That is, we are uniquely aware of our mortal nature. We understand that despite our best efforts to stay alive, death is inevitable," Routledge writes in Scientific American.

Terror management theory asserts that this juxtaposition of a desire to live and an awareness of death can cause a significant amount of anxiety, and that humans need to manage this terror in some way if we want to keep functioning.

"We would not be a very productive species if we lived our lives in constant fear of death. Thus, according to the theory, people seek out a sense of enduring meaning that makes them feel more than mortal," Routledge explains.

To put it simply, we know our lives are brief and so we try to be part of something that transcends biological existence. "This sense of death-transcendence can come from having children, creating works that will leave a lasting legacy, investing in a group or organization that outlasts the lives of any individual member, and so on," the social psychologist says.

Naturally, spirituality is a particularly powerful meaning-making tool as most religious beliefs explicitly afford humans with an afterlife.

"Research supports terror management theory," Routledge highlights. "Specifically, studies find that when people are exposed to stimuli that remind them of their mortality, they exhibit increased investment in the social and cultural identities that provide meaning and perceptions of death-transcendence."

For instance, if someone actively contemplates mortality, it increases their desire to have children, level of patriotism, religious faith, and commitment to romantic partners.

"In short, heightening the awareness of death heightens efforts to find and preserve transcendent meaning"

Similarly, Routledge says that meaning mitigates the threat of death awareness. In fact, studies show that having people think about death increases their fear of it, but this effect is only observed among those who do not perceive their lives as meaningful.

"People who have meaning are not as terrified about the fact that they are mortal," Routledge says.

Research suggests that the realization that life is finite is the driving force for our efforts to feel that our lives are purposeful and meaningful.

People want to be more than mere mortal beings who, at some point in time, disappear forever. To feel meaningful is to feel like you've made a lasting mark, and that your contribution will endure.

I know it's a stretch, but maybe, just maybe, viewing seemingly random pictures with no apparent reason behind them somehow challenges our notion of a greater purpose? But maybe that's just maybe. Maybe you're completely unfazed by this list.