I've been to 107 countries. Italy and Mexico are great, but these 5 underrated destinations should be on your travel radar.

I was immediately captivated by the fairy-tale appearance of Tallinn, the capital city of Estonia.

Walking the cobblestoned streets within the fortress-like walls of the old city transported me back to medieval times.

The city is small enough to explore on foot, and there's plenty to entertain history and architecture enthusiasts. Enjoying a coffee or a beer in the Town Hall Square while people watching is a highlight of my European travels.

Although many people visit Tallinn as a day trip from Helsinki, which is a two-hour ferry ride away, it's worth staying here for a few days and heading into the Estonian countryside. The roads are often quite empty and incredibly peaceful.

I enjoyed Estonia so much that I returned twice more in the 18 months after my first visit.

Dubai gets a lot of attention for its luxurious travel opportunities, and many know Qatar because it recently hosted the World Cup, but nearby Oman should not be skipped.

After all, Oman's capital, Muscat, provides an excellent gateway to the country.

A stroll along the beautiful Corniche will take you along the water and by the bustling Grand Bazaar. For those who love hikes, there are plenty of options in Oman, including several easily accessible trails in Muscat that offer great city views.

Better still, the amazing Wadi Shab is less than two hours from the capital city and is one of the best hikes I've ever experienced. The trail takes you through narrow gorges and across streams and ends with a surreal swim through incredible caves.

It's an experience so breathtaking I'd expected it to be packed with tourists, but it wasn't when we visited. We only saw a handful of people, which allowed us to really enjoy our trip.

I have been fortunate to go on safaris in Kenya, Botswana, and Tanzania, but Namibia is my favorite travel destination of the bunch.

While there, we rented a campervan and did a self-drive tour of the country, allowing us to explore independently. Yet again, we avoided the crowds and the campsites were usually just us and local animals.

Waking up to the sounds of monkeys, elephants, and even lions was a special treat, especially knowing we were safe inside our campervan.

In addition to the wildlife, there's a lot to explore in Namibia, including colossal dunes, which we hiked up and surfed down —undoubtedly the trip highlight for my children.

Asia has some beautiful beaches, but Sri Lanka has beaches and tea plantations, mountains, rocks, waterfalls, and more.

We visited Sri Lanka last year and hired a driver and guide who showcased the diverse landscapes of this island country. The food was terrific and extremely cheap — our family of four was fed for less than $10 on most occasions.

The locals I interacted with were incredibly friendly and the island is also small enough to allow for in-depth exploration in a relatively short time.

Growing up in Texas, my wife has been to Mexico many times since the state shares a border with the country. But to explore somewhere new, smaller, and in the same region, we chose to have our honeymoon in Costa Rica.

Although it's still popular, Costa Rica offers an authentic travel experience as I feel it has yet to be overrun by tourists. Like the other countries on this list, it has a diverse landscape, from white-sand beaches to rainforests to volcanoes, so there's plenty to do.

We also visited during the rainy season, so we took advantage of low crowds, low prices, and often received upgrades — and, as a bonus, it rarely rained!