An area spanning 14,500km, from Ghana, Togo, Benin, Nigeria, Niger, Libya, Greece, Turkey, Georgia, southern Russia and Kazakhstan, will see the moon completely cover the sun for several minutes on Wednesday.
Some countries have gone to great lengths to attract tourists and scientists, with special installations and over-the-top claims on viewing conditions.
Libya has granted astronomers normally hard to come by tourist visas and given them special permission to bring their equipment into the country.
The North African nation is to dedicate its air and sea ports to the arrival of eclipse lovers from 47 countries, including Americans, Britons and French but excluding Israelis, Shaban al-Taib, a tourism official, said.
Tent villages with a capacity for 7000 people, described as "luxuriously equipped", have been put up in the desert to accommodate the tourists.
The authorities say the country offers the best conditions for observing the eclipse, which will be visible for seven minutes in Libya.
The total eclipse will be visible from some of Turkey's biggest tourist areas, including the Mediterranean coast and Cappadocia.
Officials there say the country will offer the best chance of good weather conditions for watching the event.
"Unlike in Libya, there is no risk of sandstorms"
head of astronomy at Istanbul's Kadillia research centre
Attila Ozguc, head of astronomy at Istanbul's Kadillia research centre, said: "Unlike in Libya, there is no risk of sandstorms."
Many hotels in the region are already fully booked for 29 March, with most of the bookings coming from American and Japanese eclipse-chasers.
The tiny Greek island of Kastellorizo in the southeastern Aegean Sea, the only place in Europe where the total eclipse can be seen, is expected to be overrun with visitors.
About 1000 of them are expected, and local authorities have increased ferry boat services from neighbouring Rhodes, the sole point of contact between Kastellorizo and the Greek mainland.
A total eclipse of the sun has in many cultures traditionally been seen as a harbinger of disaster.
One of Niger's most senior Muslim figures has called on Muslims to organise group prayers, warning them that eclipses are traditionally "a call to order".
But if its supernatural effects are as yet unproved, one thing that is certain is the harmful effects of a solar eclipse on the eyes - even where the eclipse is only partial.
In Togo, where the last total eclipse seen was in 1947, people have rushed to take up a government offer of protective glasses.
Wednesday morning has been declared a national holiday in Togo, where more than 700,000 pairs of protective glasses had already been sold by 18 March, according to Kanny Sokpoh-Diallo, the population minister.