Introduction:
The first urban settlement in the world to reach a population size of one million was London. This historic city, located in the United Kingdom, achieved this milestone in the 19th century. Let's delve into the reasons why London became the first million-plus city.

Factors contributing to London's population growth:
Several factors played a significant role in London's rapid population growth and its status as the first city to reach a population of one million. These factors include:

1. Geographical Advantage:
London's location on the River Thames provided it with a strategic advantage for trade and transportation. As a major port, it attracted merchants and traders from across the world, leading to economic growth and population influx.

2. Economic Opportunities:
London became a center for commerce, industry, and finance during the Industrial Revolution. The city offered numerous employment opportunities, attracting people from rural areas and other countries in search of better livelihoods.

3. Political and Cultural Influence:
As the capital of the British Empire, London exerted significant political and cultural influence. The empire's vast territories and resources contributed to London's economic prosperity, attracting people seeking opportunities in the imperial administration, military, and other sectors.

4. Transportation Infrastructure:
London's well-developed transportation infrastructure, including the extensive railway network and the London Underground, facilitated the movement of goods and people within the city and beyond. This accessibility further fueled population growth.

5. Urbanization and Migration:
The agricultural revolution and the enclosure movement led to rural-to-urban migration in search of employment. London's growing industries and expanding services attracted migrants from all over England and other parts of the British Empire.

6. Social and Cultural Vibrancy:
London's vibrant cultural scene, including theaters, museums, and art galleries, attracted artists, intellectuals, and creative individuals. This cultural vibrancy, combined with the city's cosmopolitan nature, made it an appealing destination for people from diverse backgrounds.

Conclusion:
London's advantageous geographical location, economic opportunities, political influence, transportation infrastructure, urbanization, and cultural vibrancy were key factors contributing to its rapid population growth. These factors enabled London to become the first urban settlement in the world to reach a population of one million, making it a historic and influential city.