Below is an account of one of the Spanish expeditions of the New World in the early 16th century, and one of the most amazing tales of human audacity and perceverience I've seen.
The expedition leaves Spain in 1527 with about 600 men. About 300 of them landed on the Gulf coast of Florida, around the location of modern Tampa Bay. They intentionally sent their fleet away, marched overland to around modern Tallahassee, suffered huge losses, built rafts in part by making nails from their armor. A few men made it to the coast of modern Texas, possibly near modern Galveston, and struck overland finally arriving on the Pacific coast and meeting up there with other Spaniards. One man, de Vaca, returned to Spain in 1537 to write the following account.
A truly amazing tale.
I've reprinted the entire translated narative that I found on this PBS website:
Another (better) version (including a nice downloadable PDF) of the account is available here: http://www.americanjourneys.org/aj-070/summary/
"Expedition Cabeza de Vaca Karte" by Lencer - own work, used:Generic Mapping Tools and SRTM30-files for relief. Licensed under CC BY-SA 3.0 via Commons
Probable route of Cabeza de Vaca 1527-1537
The Journey of
Alvar Nuñez Cabeza De Vaca
Translated by Fanny Bandelier (1905)