Early Explorers 
The old children’s song “The Bear Went Over The Mountain” answers the question as to why the Bear went over the mountain as “… to see what he could see.”. (Figure 1 Ballynahinch, Co. Galway) So is the same with explorers. Man, by nature, is curious. That is how man came to Ireland – to seek out sources of food – over 10,000 years ago. When standing on the edge of the ocean, he may have wondered if there were bigger herds somewhere in a land over the horizon. Ancient tales tell of man going somewhere, seeking something. Didn’t Finn M’Coul build the Giant’s Causeway so he could find his girlfriend in Scotland? (Figure 2) (Finn seen getting wisdom). Not only is this an interesting fable, but also neatly explains why the rocks seem to resemble a series of walkways.(Figure 3) (From British stamp). It would take another thousand years or so before geologists developed the theory of how lava flowed and cooled in somewhat regular shapes.
Moving on a few millenia, we find an interesting adventurer who returned to tell his tales. Brendan, the Navigator, also known as Brendan of Clonfort (ca. 484 – ca. 577) was an early Irish monastic saint. In the early 500’s, he and a few other companions set sail in a leather currach, or horse-hide covered boat (Figure 4) (a currach or curragh) and encountered many unusual sights. For example, they came across an island of blacksmiths who hurled hot slag at them. Was this a volcano ? Most people of northwestern Europe had never heard of a volcano, much less seen one erupting and emitting hot ash. (Figure 5) (stamps of the 1994 issue). His saga, The Navigato Sancti Brendani Abbatis, was originally passed down in the oral tradition, where one story-teller memorized what another said. Could someone have decided to enhance it a bit for his audience’s interest? We know today his tale was not committed to writing until at least 400 to 500 years after his trip.(Figure 6) (StampsSelvadge illustrations from stamp set) It is known that St. Brendan traveled in the Northern Seas and established monasteries on several islands. Did he reach North America? Probably not, but definitely Iceland, and maybe Greenland. St Brendan is known as the patron saint of sailors and travelers. His feast day is 16 May.
In later times, Columbus was aware of the Navigatio. (Figure 7) (Columbus before the voyage) One important thing he was able to glean from it was that a southerly route was best for a westward trip due to wind and currents, while a more northerly route would return him to Europe. He followed this itinerary on all his trips. Today we call this the Gulf Stream route.
Not all people are interested in finding what is over the mountain. That, too, is important since building civilization is another important trait of mankind.
Reference: Wikipedia, Brendan the Navigator.