The Madurai Meenakshi Amman Temple is an ancient fortress.

1. Everyone has heard of the Eiffel Tower, the Pantheon, and the Colosseum. But the greatest architectural wonders aren't necessarily hidden in plain sight. Here are a few lesser-known wonders of the world. 2. The Meenakshi Amman Temple in Madurai, India (1655). This stunning work of Dravidian philosophy is believed to have much older origins than the 17th century, with mentions in ancient Tamil literature dating back more than 2,500 years. 3. The Shah Mosque of Isfahan in Iran (1629) is a harmonious symbol of the golden age of Persian architecture and the flourishing art of the Sasanian dynasty. The design employs complex mathematical principles, even taking into account the proportions of height and width. 4. The Two Towers of Bologna, Italy (1119). Bologna, nicknamed the "Manhattan of the medieval world," once boasted more than 180 towers, glorious symbols of wealth and power. Today, only 22 remain. 5. The most famous of these is the 320-foot Asinelli Tower. The Erechtheion in Athens, Greece (406 BC), is one of the most underrated classical wonders of the ancient world. All are places of great mystery.