Humayun's Tomb, situated in Nizzamudin east, Delhi, India, is the very first garden tomb of the Mughal Era in India. It was built in 1570, designed and built by Persian and Indian architects and craftsmen. It's design inspired the infamous Taj Mahal built after 80 years.
This tomb was declared a UNESCO World Heritage site in 1993. And from then on
the restoration work is constantly going on to preserve this world heritage site.
Other than the main central tomb there are a few other tomb encompasses it.
Tomb of Isha Khan
This tomb is on the west side of main Humayun's tomb and actually predates it by arount 20 years. Isha Khan was an Afghan Nobel, in the court of Sher Shah Suri, of Suri Dynasty.
Isha Khan Mosque
This mosque is facing Isha Khan's tomb.
Garden Complex
A beautiful garden encompasses the tomb from all directions. This is the first garden-tomb to be built in India.
Architecture
The tomb is built of red sandstone and rubble masonary and white marble is used as flooring and as a cladding material.
Humayun’s garden-tomb is an example of the charbagh (a four quadrant garden with the four rivers of Quranic paradise represented), with pools joined by channels. The garden is entered from lofty gateways on the south and from the west with pavilions located in the centre of the eastern and northern walls. source
Humayun's Tomb Garden Enclosure Plan. Image source
Ceiling of Entrance Chamber. Image source
Stone Lattice Window
Second Storey
Note: All the above images are provided by me 