Arguably, India’s Taj Mahal is the most world’s most sublime building.
However, Agra is not the global hotspot for prime examples of Mughal architecture and its decoration.
Lahore – Pakistan’s second largest city – has the largest number of bona fide “jaw-dropping” Mughal constructions.
(I think Lahore is also a much more generally-rewarding/likeable destination than is Agra)
The last Mughal mosque – the world’s largest mosque, when constructed in 1671-73 – is in Lahore.
Lahore’s Old City is much less frenetic than Old Delhi, but the former is much the richer, architecturally.
Agra’s Red Fort is stupendous, but Lahore Fort is even more so.
Above, you are looking at merely a small section of Lahore Fort’s picture wall.
The world’s biggest such “mural” occupies circa 6,600 square metres of the fort’s exterior.