The Taj Mahal complex is bounded by crenellated red sandstone walls on three sides with river-facing side open. Outside these walls are several additional mausoleums, including those of Shah Jahan's other wives, and a larger tomb for Mumtaz's favorite servant. These structures, composed primarily of red sandstone, are typical of the smaller Mughal tombs of the era. The garden-facing inner sides of the wall is fronted by columned arcades, a feature typical of Hindu temples later incorporated into Mughal mosques. The wall is interspersed with domed kiosks (chattris), and small buildings that may have been viewing areas or watch towers like the Music House, which is now used as a museum.
The main gateway (darwaza) is a monumental structure built primarily of
marble and is reminiscent of Mughal architecture of earlier emperors. Its archways mirror the shape of tomb's archways, and its pishtaq arches incorporate calligraphy that decorates the tomb. It utilises bas-relief and pietra dura (inlaid) decorations with floral motifs. The vaulted ceilings and walls have elaborate geometric designs, like those found in the other sandstone buildings of the complex.
At the far end of the complex, there are two grand red sandstone buildings
that are open to the sides of the tomb. Their backs parallel western and eastern
walls and these two buildings are precise mirror images of each other. The
western building is a mosque and its opposite is the jawab (answer) whose
primary purpose was architectural balance and may have been used as a
guesthouse. The distinctions between these two buildings include the lack of
mihrab, a niche in a mosque's wall facing Mecca, in the jawab and that the
floors of jawab have a geometric design, while the mosque floor was laid with
outlines of 569 prayer rugs in black marble.
The mosque's basic design is similar to others built by Shah Jahan, particularly to his Masjid-i-Jahan Numa, or Jama Masjid of Delhi, a long hall surmounted by three domes. The Mughal mosques of this period divide the sanctuary hall into three areas with a main sanctuary and slightly smaller sanctuaries on either side. At Taj Mahal, each sanctuary opens onto an enormous vaulting dome. These outlying buildings were completed in 1643.