What special day do more than 30 countries around the world observe each year – nations as diverse as the United States, Afghanistan, China, India, Mexico, Peru, Russia and Yemen? The specific date may vary from country to country, but they all celebrate a Teacher Day.

In our country, National Teacher Day is on May 3 this year. That dovetails with National Teacher Appreciation Week, May 2-6. The National Education Association and the National PTA encourage us to use that time as an opportunity to honor teachers and thank them for the lasting contributions they make to our lives. Let’s all make a special effort to do that this year.

Why do teachers deserve our praise and support? The short answer is because they play such a key role in our society.

“Every day in schools across the country, teachers touch the lives of millions of children, and their work and impact extends far beyond the boundaries of the classroom,” according to the National PTA.

Think about it. If asked to name the top three or four people who most influenced our lives while we were growing up, many of us would include the names of one or more teachers.

Doing what teachers do is not easy. U.S. teachers, on average, work more than 52 hours a week, including 30 hours on instruction and 22 hours on tasks like preparing lessons and grading papers, the National PTA says. And we all know teachers who dedicate even more time to helping their students.

In fact, U.S. Sen. Susan Collins, R-Maine, praised teachers for their “tireless efforts” last May as she helped introduce a bipartisan resolution in the Senate to recognize and thank the nation’s teachers. “America’s teachers are among our most dedicated public servants,” Collins said.

President Obama, in a teacher appreciation proclamation he issued last May, said, “Our best teachers are role models who … encourage our children’s passions, inspire their imaginations and help them realize the best versions of themselves.”

At the Portland Public Schools we have many such inspirational teachers. We are so grateful for everything they do to ensure our students are prepared for success in college and careers.

I don’t have space here to list all our great teachers, so I’ve chosen two by way of example. One is a relatively new teacher: Lyman Moore Middle School ELL teacher Tyler Jellison, who joined our district four years ago after spending four years teaching English in Cambodia. The other is English teacher Sandra Guerra, who is retiring this summer after 45 years at Portland High School.

Lyman Moore Principal Stephen Rogers said, “Tyler is everything you want in a teacher. He has a positive, can-do attitude that is infectious – and crucial for working with middle level students. He holds very high standards for behavior and academics, while providing scaffolded systems to assure that all students will get there with varying degrees of support. He also contributes beyond the classroom, by giving time to whatever is needed for students, in programs such as Model UN.”

PHS Principal Deborah Migneault said that in more than four decades as an educator, “Ms. Guerra never lost her passion for teaching nor her deep commitment to students.”

One of Guerra’s colleagues, David Levasseur, cluster coordinator for the PHS English Department, said, “Sandra Guerra has long been recognized as an outstanding teacher in the Portland area and throughout Maine. … The positive impact she has had on the city of Portland will last for years.”

What fuels these teachers in this demanding profession?

Guerra said, “Most rewarding is seeing my students realize their dreams and go on to do wonderful things with their lives.”

Jellison said, “The biggest reward is seeing a student grow from a child that is completely consumed by their little bubble of a world to a young adult that is concerned about the larger world around them. My greatest moments are when I see that light bulb go on and that young adult sees that they are important and part of something bigger. Those small moments make all the other struggles and frustrations go away.”

Jeanne Crocker is interim superintendent of the Portland Public Schools. She can be reached at superintendent@portlandschools.org.