San Juan is a perfect specimen of a walled town, with portcullis, moat, gates, and battlements.  The wall surrounding this town is defended by several batteries.  Facing the harbor are those of San Fernando, Santa Catalina, and Santa Toribio.  Looking toward the land side is Fort Abanico, and toward the ocean the batteries of San Antonio, San Jose, and Santa Teresa, and Fort Princesa.  The land part has two ditches, or cuts, which are easy to inundate.  The fort and bridge of San Antonio that of San Geronimo, and the Escambron battery situated on a tongue of land which enters the sea.  Built over two hundred and fifty years ago, the city is still in good condition and repair.  The walls are picturesque, and represent a stupendous work and cost in themselves.  Inside the walls the city is laid off in regular squares, six parallel streets running in the direction of the length of the island and seven at right angles.

The peninsula on which San Juan is situated is connected with the mainland by three bridges.  The oldest, that of San Antonio, carries the highway across the shallow San Antonio Channel.  It is a stone-arched bridge about 350 yards long including the approaches.  By the side of this bridge is one for the railroad and one for the tramway which follows the main military highway to Rio Piedras.

Among the buildings the following are notable:  The palace of the Captain-General, the palace of the intendencia, the town hall, military hospital, jail, Ballaja barracks, theater, custom house, cathedral, Episcopal palace, and seminary.  There is no university or provincial institute of second grade instruction, and only one college, which is under the direction of Jesuit priests.  The houses are closely and compactly built of brick, usually of two stories, stuccoed on the outside and painted in a variety of colors.  The upper floors are occupied by the more respectable people, while the ground floors, almost without exception, are given up to the negroes and the poorer class, who crowd one upon another in the most appalling manner.

The population within the walls is estimated at 20,000 and most of it lives on the ground floor.  In one small room, with a flimsy partition, a whole family will reside.  The ground floor of the whole town reeks with filth, and conditions are most unsanitary.  In a tropical country, where disease readily prevails, the consequences of such herding may be easily inferred.  There is no running water in the town.  The entire population depend upon rain water, caught upon the flat roofs of the buildings and conducted to the cistern, which occupies the greater part of the inner court-yard that is an essential part of Spanish houses the world over, but that here, on account of the crowded conditions, is very small.  There is no sewerage, except for surface water and sinks, while vaults are in every house and occupy whatever remaining space there may be in the patios not taken up by the cisterns.  The risk of contaminating the water is very great, and in dry seasons the supply is entirely exhausted.  Epidemics are frequent, and the town is alive with vermin, fleas, cockroaches, mosquitoes, and dogs.