What is the third level that Charley mentions?

In The Third Level, the “third level” that Charley mentions is a mysterious and seemingly imaginary platform at Grand Central Station in New York City. Charley accidentally discovers this level, which appears to be a portal to a bygone era—the year 1894. Unlike the modern, bustling station, this third level is quiet and filled with people dressed in 19th-century clothing, with gaslights and old-style train carriages. The third level symbolizes Charley’s deep desire to escape the stress of modern life and find peace in a simpler, nostalgic past. It represents a psychological refuge from the pressures of the present day.

This question related to Chapter 1 English Vistas Class 12th NCERT.
From the Chapter 1. The Third Level.
Give answer according to your understanding.