Cuba is in party mode this week, despite tough economic times worsened by tighter U.S. sanctions, as it prepares for its first state visit by a Spanish king, to celebrate the 500th anniversary of the founding of Havana, the capital.

Spain's King Felipe and Queen Letizia arrived late on Monday for a three-day stay to commemorate the Cuban capital, founded by a Spanish conquistador on November 16, 1519, and considered one of the architectural jewels of Latin America.

The royal trip also underscores Europe's rapprochement with Cuba's Communist government, even as the United States doubles down on a decades-old policy of sanctions.

Events to mark Havana's anniversary include the inauguration of renovated landmarks, concerts, the illumination of city fortifications and a rare fireworks display over the Malecon seafront boulevard.

"We Cubans like to party," said trade union worker Miryelis Hernandez, 32. "Even if we are feeling low, we know we have to pick ourselves up, so it's good Havana is celebrating its 500 years and there is a party."

The royal couple will tour Havana's old historic center, a UNESCO World Heritage site boasting an eclectic mix of colonial, Art Deco and other styles that has been undergoing a slow facelift since the 1990s.

Cuba focused more on building infrastructure in the impoverished countryside than on maintaining its cities in the early decades of Fidel Castro's leftist 1959 revolution.

"Havana luckily conserved its valuable architectural patrimony, unlike other Latin American cities that lost a good part of their historic centers' patrimony due to real estate development," said Cuban urban planning specialist Gina Rey.

"But paradoxically this patrimony is very deteriorated, and (renovation) efforts have not been enough so far."

One of the main buildings on show for the celebrations will be the Capitol, a neoclassical gem built in 1929 and inspired by Washington's Capitol.