The unicorn is the official national animal of Scotland and continues to feature on Royal Coat of Arms today.
For Sunday, willow artist Woody Fox has created a 2.1m (7ft) unicorn sculpture for the Crawick Multiverse art project in Dumfries and Galloway.
VisitScotland is also encouraging people to "spot" unicorns elsewhere in Scotland.
Carvings and sculptures of unicorns can be found on historic buildings, such as the National War Museum at Edinburgh Castle.
A tapestry called, Mystic Hunt of the Unicorn, hangs in Stirling Castle and a unicorn is a feature of a fountain in the courtyard at Linlithgow Palace.
On the Black Isle in the Highlands, The Stables in Cromarty has a large unicorn sculpture.
The unicorn has been a Scottish heraldic symbol since the 12th Century when it was used on an early form of the Scottish coat of arms by William I.
Reasons for the appearance of a unicorn include a theory that narwhal, a whale with long tusks protruding from their heads, were seen in Scottish waters after straying from their usual range in the Arctic.
Unicorns were also written about by the ancient Celts, Persians, Romans and Greeks, and were often described as an elegant white horse-like creature with a single horn capable of magical properties.
Wales and England are among other nations that also celebrate fabled beasts. The Welsh flag features a red dragon connected to one of the country's legends, while England's patron saint St George is said to have killed a dragon.
Artist Fox's other artwork has also involved animals, but of varieties that can be found running around the Scottish countryside.
He said: "I was thrilled to be asked to create this unique sculpture of a unicorn to mark National Unicorn Day.
"My previous work includes deer, badgers, foxes and rabbits which bring homes, gardens, parks and public spaces to life.
"It has been very inspiring for me to work on this noble and spiritual animal for the first time and to help promote Scotland at the same time."

The three-day tie begins on 7 April, five days after the Miami Open, which is played outdoors on a hard court.
World number one Andy Murray, who sat out Britain's 3-2 victory over Canada in the Davis Cup World Group first round, is expected to play in Miami.
Britain beat France in the quarter-finals in 2015, when they won the title for the first time in 79 years.
Murray, 29, said earlier this month he expected to return against France after a break following his fourth-round exit from the Australian Open.
Rouen's Palais des Sports can accommodate 5,200 spectators.

There will also be daily reports after each session and contributions from the 5 live F1 team from the second test - as well as a special 5 live season preview show coming from Barcelona on March 3.
The 2016 season gets under way on 20 March, with the first race in Melbourne, Australia.
Circuit de Catalunya, Barcelona - 22-25 February
Circuit de Catalunya, Barcelona - 1-4 March
Ferrari - launched
Haas - launched
Force India - launched
Renault - launched
McLaren - launched
Mercedes - launched
Red Bull - launched
Sauber - 1 March
Toro Rosso - launched
Williams - launched
Manor - launched

The central bank's past efforts to spur growth have disappointed investors and there is expectation of more monetary easing from the meeting on Thursday.
Japan's Nikkei 225 index fell 0.5% to close at 17,353.28.
Embattled Mitsubishi Motors again saw its shares tumble, losing 9.6% over the day.
The Japanese car maker is engulfed in a scandal over falsifying fuel efficiency.
In China, the mainland benchmark Shanghai Composite closed 0.6% higher at 2,964.70 while in Hong Kong the Hang Seng ended up 0.5% at 21,407.27.
In South Korea, the Kospi index finished the day up 0.3% at 2,019.63, despite the country reporting its slowest quarter of economic growth in nine months.
In the January to March period the economy grew by 0.4% compared with the previous quarter, which was in line with expectations. On an annual basis, the economy expanded 2.7%.
In Australia, traders were equally cautious, and the ASX/200 index fell 0.3% to 5,220.64.
Tourism organisation VisitScotland is encouraging people to celebrate Sunday's National Unicorn Day.
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Great Britain's Davis Cup quarter-final against France in April will be played on an indoor clay court in Rouen.
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You can follow Formula 1 testing on BBC Sport live, with track updates, expert analysis, social media reaction, debate, voting, the latest pictures and more from Barcelona.
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Japanese shares fell for a second day as investors remained cautious ahead of a key Bank of Japan meeting later this week.