"The cake measures 3.63 meters (11.9 feet) long, 2.5 meters high and almost 2 meters wide. It's made of vanilla (and) chocolate and filled with 'dulce de leche' (caramelized condensed milk)," pastry chef Eduardo Ruiz told Efe news on Thursday.
The cake, for which more than 2,200 kilograms (4,840 pounds) of flour was used and which about 100 people worked to prepare, is a 1:20 scale replica of the Historical District of Old Panama, which was declared a UNESCO World Heritage Site in 2003 and is one of the country's most important tourist attractions.
The enormous pastry was to be unveiled amid the ruins of the archaeological site, but the intense rain on Thursday in the area forced organizers to move the event under an improvised arcade. Panamanian artist Anny Tovar was tasked with singing "Happy Birthday" to the city.
The festivities also included a parade in which about 100 musical bands participated with former world champion boxer Roberto Duran as the standard-bearer, along with actors outfitted as colonists and local Indians.
"It's a very special day despite the rain. The water is much needed, it's a blessing and the cake is remaining in really good shape," Lourdes Cabrera, a 40-year-old Panamanian who attended the celebration with her whole family, told EFE.
The events agenda included artistic presentations in stations of the city's metro, the only one in Central America.
Arias Davila founded the city on Aug 15, 1519, and it served as the departure point for numerous expeditions throughout the region and the collection point for the gold extracted in Peru, which was then transported by mule to the town of Portobelo, where it was loaded onto galleons for shipment to Spain.
The city was sacked and destroyed in 1671 by the famous English pirate Henry Morgan and the local authorities decided to rebuild at a spot 10 km to the southwest, erecting a city wall around a zone now known as the Old City, which each day welcomes hundreds of tourists.
Now, with its impressive skyline, Panama City is a financial center known as the "Latin American Miami," and some 1.5 million people - almost 40 percent of Panama's total population - live in the metro area, which features a busy international airport and the entrance to the Panama Canal, through which 6 percent of the world's trade passes.
Capital Mayor Judy Meana told the media that the city's main challenge at present is "ending inequality" among the population and erasing the pockets of poverty that still exist there.
Panamanian President Laurentino Cortizo is scheduled on Thursday to hold a cabinet meeting to discuss tourism amid the ruins of Old Panama.