Okay, I need to create a professional Wikipedia-style document about "Urban Planning" under the categories of Environment, Urban and Regional Development, and Planning. Let me start by understanding the requirements.

First, the structure: H1 for the title, an overview section, several sections with H2 and H3 headings, and maybe references or related documents. The content needs to be accurate, objective, detailed enough, easy to read, and use technical terms with explanations. Also, markdown formatting with proper hierarchy, lists, tables, emphasis, and code blocks if needed. It should be at least 800 characters.

Starting with the title: "도시 계획" as given. Then an overview section explaining what urban planning is, its importance, key objectives, etc. Next sections could include history, key components, challenges, examples, and maybe a conclusion or references.

For the history section, I should mention ancient cities like Rome or medieval European towns, then move to modern developments in the 19th and 20th centuries, including figures like Ebenezer Howard and the Garden City movement. Also, post-war urban planning and contemporary approaches.

Key components: Land use zoning, transportation systems, infrastructure (utilities, public services), environmental sustainability, community engagement. Each of these can be H2 sections with subpoints as H3.

Challenges might include population growth, climate change, social inequality, funding issues. Maybe also mention specific challenges like urban sprawl or aging infrastructure.

Examples could be cities known for good planning: Copenhagen's bike-friendly design, Singapore's green initiatives, Curitiba's bus system. Each example can have a brief description under an H2 section.

Need to ensure technical terms are explained. For instance, "zoning" should be defined. Also, check that the content is balanced and covers different aspects without being too shallow.

I need to avoid markdown in the thinking process but make sure the final answer uses it correctly. Let me structure each part step by step, making sure each section flows logically. Check for clarity and conciseness, ensuring that each paragraph isn't too long. Use bullet points or lists where appropriate, like under key components.

Also, verify that all information is accurate. For example, Ebenezer Howard's Garden City concept was in the early 20th century. Mentioning specific examples helps illustrate points. Maybe include a table comparing different urban planning approaches if it adds value, but not sure yet. Alternatively, use code blocks for any relevant data or diagrams, though that might be less common here.

Finally, ensure the document meets the length requirement by expanding each section sufficiently without being redundant. Check for grammar and readability. Make sure to include a references or related documents section at the end if needed.