Did you know that explorer Marco Polo once encountered a Unicorn?  He was a little disappointed and unimpressed by it though.  From Book 3, Chapter 9 of his travels he leaves the kingdom of Ferlec to that of Basma and describes the place and wildlife:

There are wild elephants in the country, and numerous unicorns, which
are very nearly as big. They have hair like that of a buffalo, feet like
those of an elephant, and a horn in the middle of the forehead, which
is black and very thick. They do no mischief, however, with the horn,
but with the tongue alone; for this is covered all over with long and
strong prickles [and when savage with any one they crush him under their
knees and then rasp him with their tongue]. The head resembles that of a
wild boar, and they carry it ever bent towards the ground. They delight
much to abide in mire and mud. ‘Tis a passing ugly beast to look upon,
and is not in the least like that which our stories tell of as being
caught in the lap of a virgin; in fact, ’tis altogether different from
what we fancied.

Okay, so what Marco describes is, obviously to us now, a Rhinoceros.  One curiosity is that he seems to be describing an Indian rather than Sumatran Rhino (which has two horns).  Maybe it escaped from a zoo or something.