I got a very nice explanation from him:
This beautiful building is a tomb for Humayun who was the
second ruler in the Mughal Dynasty (1526-1850's) whose
reign lasted through roughly the late 16th century. His
dynasty was mostly of Central Asian descent (and
Afghanistan too) but also of Persian royal descent, and
under his rule Central Asia and northern India went through
a renaissance of Persian influence in all aspects of
culture.
The tomb is in Old Delhi (15 km from New Delhi), the seat
of power for the Mughal Empire in Northern India. It is
built using local red sandstone with hints of yellow
sandstone, white marble (of Taj Mahal fame) and many other
stones both precious and not. It is said to be quite
exactly like the Taj Mahal in proportion and plan. Humayun
is the grandfather of Shahjahan who built the Taj Mahal for
his queen.
So on my trip earlier this year I toured the seats of
Mughal power through north India and saw some truly amazing
recurring themes. Many of these rulers, though established
in Islam, often had queens from various places and the
local queens were Hindu. So many palaces are decorated with
a variety of styles: Muslim iconography, Persian style,
Hindu style, Buddhist style and so on. I noticed a whole
hell of a lot of six pointed stars all over Muslim
buildings and I was told by guides that these were very
common in older Muslim iconography. There are a lot of
geometric aspects that are common including 8 pointed stars
as well. But the 6 pointed stars surprised me a bit so I
clicked the pic.
Interestingly enough, Humayun's son Akbar, being known for
his righteousness and intelligence, gathered a group of
inter-faith scholars during his reign and established a new
religion that represented the truth from all the religions
represented in his kingdom. It was called Din-i-Ilahi and I
encourage you to check it out on wikipedia.