Stereoview of the Western Entrance of the Hoosac Tunnel Taken From the Interior of the Tunnel During its Construction Near North Adams, Massachusetts (1860's/1870's)

Stereoview of the western entrance of the Hoosac Tunnel taken from the interior of the tunnel during its construction near North Adams, Massachusetts, c. 1860-1875. By Hurd and Smith.

Source: New York Public Library.

View of Construction of the Echo Bridge Over the Charles River Near Needham, Massachusetts (1876)

View of construction of the Echo Bridge over the Charles River near Needham, Massachusetts, August 17, 1876.

Source: New York Public Library.

A Group of Men Posing in Front of a Public School Under Construction in Leavenworth, Kansas (1867)

A group of men posing in front of a public school under construction in Leavenworth, Kansas, 1867. By Alexander Gardner.

Source.

Calotype View of Workers Standing on a Cast Iron Lighthouse Assembled Temporarily at the Foundry Where it Was Created in Philadelphia Before Its Shipment For Installation on Carysfort Reef in Florida (1849)

Calotype view of workers standing on a cast iron lighthouse assembled temporarily at the foundry where it was created in Philadelphia before its shipment for installation on Carysfort Reef in Florida, August 2, 1849. By the Langenheim brothers.

Source.
Wikipedia entry.

Union Troops Constructing a Bridge Over Rappahannock River in Fauquier Sulphur Springs, Virginia (1862)

Union troops constructing a bridge over north fork of the Rappahannock River in Fauquier Sulphur Springs, Virginia, August 1862. By Timothy O'Sullivan. Animated stereoscopic photographs.

Source.

The Pennsylvania Hospital for the Insane During its Construction (1859)

Workers posing in front of the new Pennsylvania Hospital for the Insane during its construction, Philadelphia, 1859. The well-dressed men posing in the foreground are possibly the architects, engineers, hospital administrators or some combination of those jobs. Animated stereoview.

Source.

Time-lapse Daguerreotypes Showing the Pont Neuf Bridge in the Process of Being Rebuilt (1852)

Time-lapse daguerreotypes showing the Pont Neuf bridge in Paris in the process of being rebuilt, c. 1852.

Source.