Inside the walled city at Agra, India 2013

A moat and high red brick walls to keep pesky invaders at bay. 

Inside the Agra Fort. The red sandstone is not only amazingly pretty, it also keeps the area cool inspite of the scorching heat.

The Diwan I Am, the hall of public audience.

White marble buildings, with intricately carved walls and ceilings, inside the fort.

Ladies enjoying the view of the gardens and the Sheesh Mahal (the glass palace), built by Shah Jahan for his baths.

One of the highlights of the trip. We were led inside the Sheesh Mahal through dark passages, with only a small flashlight guiding our way. Inside was damp and cool; it felt much like being inside a seashell. We were asked to stand by a wall on one side of the room, while the man with our guide lit candles across from us. Suddenly, the walls and ceilings became alive--a thousand fireflies dancing around us.  

Entry walls of the Agra Fort.

Our tour guide telling us about the many emperors that the fort has outlived. Today, a part of the fort is still being used by the Indian military (the Parachute brigade).

Another angle of the Sheesh Mahal.

Columns and walls inlaid with semi-precious stones such as turquoise, malachite, lapis lazuli, etc. 

A family picture outside the Jahangir Palace, the largest part inside the Agra fort. The palace was built by Emperor Akbar in the 16th century  for his son, Jahangir, and his son;s wife, wife Nur Jahan.

About the Agra Fort from Wikipedia:
The present-day structure was built by the Mughals, though a fort had stood there since at least the 11th century. Agra Fort was originally a brick fort known as Badalgarh, held by Raja Badal Singh Hindu Sikarwar Rajput king (c. 1475). It was mentioned for the first time in 1080 AD when a Ghaznavide force captured it. Sikandar Lodi (1488–1517) was the first Sultan of Delhi who shifted to Agra and lived in the fort.