Subz Burj v/s Nila Gumbad - no they are not the same!

Here's the beautiful Subz-Burj, at the intersection of Mathura Road and Lodhi Road. Subz means Green in Arabic, Burj means Tower.  The tiles on top of the tower suppposedly used to be green, but were replaced by blue tiles during restoration by ASI in the 80's (or at least that's what I am told). Subz Burj is a tomb. No one knows who's buried in it.

Because of the colour of the roof tiles, there's an unfortunate tendency to mix up Subz Burj (Green Tower) with Nila Gumbad (Blue Dome), which is the name of an entirely different monument near Humayun's Tomb.

Nila Gumbad in foreground. Humayun's Tomb is to the top left. Nai ka Gumbad is in between.
Photo from Archnet: Link here

Nila Gumbad is also supposed to be a tomb. The ASI says it's the earliest Mughal tomb in India, and reflects an architectural style without any Indian influences. It is believed to contain the remains of a man called Miyan Fahim Khan. He was the attendant/servant of the poet Rahim (Abdur Rahim Khan-i-Khana). What this attendant did to deserve burial in such a grand tomb, I don't know. To top that, there is no structure inside the tomb, no sarcophagus to show that someone is buried there.

Here's a map showing where Subz Burj is, with respect to Humayun's Tomb and Nila Gumbad:

Humayun's Tomb was listed under the UNESCO World Heritage list in 1992. This month the listing was expanded to list several other tombs and complexes in the vicinity of Humayun's Tomb, thereby doubling the area under the heritage list. While Nila Gumbad is now included in the list, Subz Burj is now in the buffer zone.

So - to summarise the differences:
Subz Burj - Originally green and now blue; Nila Gumbad - Always has been blue
Subz Burj - Now a traffic roundabout (Lodhi Road - Mathura Road intersection). Nila Gumbad - Adjoining the Humayun's Tomb complex
Subz Burj - built somewhere in mid-1500's, no one knows who is buried here. Nila Gumbad - said to be the oldest Mughal ruin, but I can't find a date online for when it was built. Later in mid-1600's,  Miyan Fahim said to be buried here.
Subz Burj - lies in the buffer zone of Humayun's Tomb; Nila Gumbad - listed under world heritage site list.