The construction of the main palace and the surrounding estate of Quinta da Regaleira in Sintra, Portugal, took approximately six years. The project was conceptualized by the Brazilian-Portuguese millionaire António Augusto Carvalho Monteiro and designed by the Italian architect Luigi Manini. Construction officially began in 1904 and was completed in 1910. While six years might seem relatively short for such an intricate "Gothic Revival" masterpiece, the speed was a testament to Monteiro's vast wealth and the focus of the workforce on the 4-hectare estate. The timeline covers not just the ornate house with its gargoyles and pinnacles, but also the legendary "Initiation Wells," the hidden tunnels, and the various chapels and grottos that make the site a labyrinth of Masonic and alchemical symbolism.