Final answer:
A 'megaproject' may cost US$1 billion or more, affect millions of people, and take years to complete. It is an immense undertaking with significant economic impact, often involving complex planning and substantial financial investment in sectors like infrastructure or energy.
Step-by-step explanation:
A very large project may be referred to as a 'megaproject'. As a guideline, megaprojects cost US$1 billion or more, affect 1 million or more people, and run for years. Megaprojects are significant undertakings that involve large financial investments, vast resources, and complex planning.
Understanding the scale of these projects is crucial. For instance, the fact that a few hundred billion dollar gain is a significant amount of money that persists annually indicates the level of economic impact these megaprojects can have. Evaluating these projects requires weighing their massive costs against their potential benefits, like how government regulators determine reasonable regulations by estimating potential savings in terms of lives vs project expenses.