During the 16th and 17th century Madrid hardly felt and certainly didn't look like other European capitals, a fact that Spanish monarchs were increasingly aware of. Slowly new buildings were constructed and thanks to the Borbones Madrid slowly began transitioning from a town to a city; it was with Carlos III, however, that things really began to take shape.
Carlos III saw great potential in the city and had big plans for its future; luckily, he also had the ambition to get things moving. Urban planners and architects were brought in and given large constructions to build and elegant green spaces to create. Architecture became grander and more ornate, drawing influences from France and Italy, and began to look like a capital city should.
On one side of the city, up went the city's emblematic Palacio Real (Royal Palace), designed by Italian architects Filippo Juvarra and Giambattista Saccheti, while at the opposite extreme the city city was expanded beyond the Huertas neighborhood and into what had been a large green field, or "prado". A long gardened boulevard - the Paseo del Prado - was installed, and Carlos III imagined it flanked by different buildings dedicated to science, thus the Botanical Garden and Astronomical Observatory that you'll find here. In fact, the sprawling Prado art museum was intended to be dedicated to the natural sciences. On each end of the Paseo del Prado you'll find classically inspired fountains of Neptuno and Cibeles.
While in the area, you'll also see the Atocha train station and the massive Puerta de Alcalá. Finally, your tour of the Madrid de los Borbones wouldn't be complete without a stroll through the sprawling Retiro Park, where you can enjoy the rose garden, the walking paths, the Glass Palace and more.