Which capital is the only one with a non-rectangular national flag?

Kathmandu is the capital associated with the world’s only non-rectangular national flag: Nepal’s distinctive double-pennon flag.

Nepal’s flag consists of two joined triangular pennants, forming a concave shape rather than a rectangle or square. Its crimson red field represents bravery and is also linked with Nepal’s national flower, the rhododendron. A blue border symbolizes peace, while the moon and sun traditionally express the permanence and endurance of the nation.

The modern design was standardized in 1962, although its two-pennant form has much older roots in South Asian and Himalayan banner traditions. Nepal’s constitution provides unusually precise geometric instructions for constructing the flag, including the proportions, borders and placement of its symbols.

The wording can cause a small mix-up: the flag itself belongs to Nepal, while Kathmandu is the capital city used as the quiz answer. Dhaka, Delhi and Thimphu all have capitals with conventional rectangular national flags. Nepal’s flag is also unusual because it is taller than it is wide, unlike almost every other sovereign national flag.