Completed between 1612 and 1614 as per inscriptions on its south gate, the construction of the mausoleum is said to have commenced during emperor Akbar's (1556-1605) lifetime in 1604 but concluded during his son, Jahangir's reign (1605-1627). This is perhaps accurate, as the Akbarnama states nothing about the description of the monument except for noting Behistan or Behistabad (Abode of Paradise) in Sikandra as the burial place of the emperor. Recorded references to the tomb are mostly from Jahangir's rule; they mention his discontent with the initial progress on the mausoleum and outline his active involvement in its design, modification and embellishment.
The mausoleum complex is square in plan and aligned on the cardinal axis, with the tomb at its center and four gates, one along each wall. Based on a charbagh, or walled square garden composition much like his father Humayun's (1530-1540, 1555-1556) tomb, the tomb of Akbar has a tall sandstone clad gate with ornate marble inlay carvings and inscriptions. It consists of a colossal arched niche flanked on either side by double-stacked balconies. Surmounting the gate pavilion are four towering white marble minarets, one at each corner. Its inscriptions were written and designed by Abd al- Haqq Shirazi (later known as Amanat Khan), famed calligrapher of Mughal monuments including Taj Mahal. While the inscriptions on the north elevation facing the tomb eulogize the deceased emperor, those above the entrance praise Jahangir, the patron of the tomb.
Beyond the lofty gate lies the charbagh divided into quadrants by watercourses designed to evoke the rivers of paradise. Hence, the mausoleum itself is physically and metaphorically located at the center of a heavenly garden, Behistan. A paved causeway leads from the gate to the mausoleum. It is a five-tiered structure much like a truncated pyramid enveloped by low galleries. The domed and vaulted galleries are a hundred and five meters long serving as a large square plinth for the four square stories located at their center, each of which steps in as the structure rises. The gallery space is rhythmically arranged with massive pillars supporting arches roughly 6.7 meters apart. The central bay of each side is marked by a high pishtaq surmounted by a rectangular chattri, or roof kiosks. Only the southern pishtaq gives access to the burial chamber, a small square room at the end of long corridor at the heart of the building domed at eighteen meters. Of the vaulted bays behind the four pishtaqs, the southern one is the most elaborate in ornamentation. The burial chamber also houses the tombs of the emperor's daughters, Shakrul Nisha Begam and Aram Bano.
Outside, the second story has an arcaded verandah on each side, which is composed of twenty three bays. The arcades are repeated on the subsequent floors forming peripheral walkways at each level and chattris at the corners. The top floor has no superstructure but consists on an open terrace enclosed with marble screen parapets. This five-tiered structure with its pillared terraces and numerous chattris also bears a striking resemblance to the Panch Mahal at Fatehpur Sikri.
Sources:
Asher, Catherine B. The New Cambridge History of India: Architecture of Mughal India. Cambridge: Cambridge University Press, 1992. 105-110
Farell, Thomas. Mughal Architecture II. Ann Arbor: Center for South and Southeast Asian Studies and Asian Art Archives, University of Michigan, 1978. 1-8
Koch, Ebba. Mughal Architecture: An Outline of its History and Development, 1526-1858, Munich: Prestel Verlag, 1991. 70-71
Tillotson, G.H.R. Mughal India. San Francisco: Chronicle Books, 1990. 85-88.