Off the Bricks

Pack 01

Underground Boston Walking Tour: Mail Tubes, Ghost Platforms and the First Subway

Boston built America's first subway in 1897, and most of what it built is still running. Off the Bricks: Under Boston is a self-paced riddle walk from North Station to the Common that follows the city's hidden infrastructure.

You'll solve a riddle, walk to a spot, and find the answer by looking at something real: a street sign, a carved inscription, a pair of chimneys on a roof. Then you get the story, and it's sourced. We read the Boston Transit Commission's annual reports from 1895 to 1905, the federal reports on the pneumatic mail tubes, Big Dig-era Globe reporting and the Greenway's own paperwork. Where the usual story is wrong, we say so and show you who said what.

Along the way: the mail that moved under the streets by compressed air, a graveyard that breathes for the Green Line, a park that is the roof of a seven-level garage, a mural wall that exists to feed air to a highway, a steam plant from 1929, and the corner where the first subway nearly ended before it opened. There's a thirteenth stop for anyone who keeps walking, a short cut of six stops if you've only got an hour, and two detours a T ride away.

About two and a half hours, roughly four kilometers, mostly flat. Start at North Station, end at Boylston. Nothing requires going anywhere you shouldn't: no tunnels, no rooftops, no closed stations. Just the city you walked past, read closely.

Play any two stops free.

Route

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Map data © OpenStreetMap contributors

  • The whole walk

    150 MIN · 3.9 KM · 13 STOPS

  • The short cut

    60 MIN · 1.8 KM · 6 STOPS

    In an hour: a kettle the city measured, a graveyard that breathes for the subway, a station cut into the Old State House, the square where mail went by air, the corner that blew up in 1897 and two streetcars parked on a dead track.

Stop 01 · West End / Bulfinch Triangle

Canal Street was widened for the first subway, which came up for air in the next block.

The street on that sign was rebuilt for the subway: the city took a 25-foot strip from the Boston & Maine railroad and widened Canal Street to 75 feet, and on September 3, 1898, the subway's north end opened beside it: a four-track ramp in the block south of Causeway, between Canal and Haverhill. Mayor Josiah Quincy asked for the space over the ramp, '19,526 feet' by his count, for a city building.

A second underground Boston surfaced here too. In December 1897 the city's first pneumatic mail tube opened between the post office in Post Office Square and the North Postal Station on Causeway Street, by North Union Station. It came up School Street, Beacon, Bowdoin, Derne, Staniford and Causeway, laid out on purpose to stay clear of the subway being dug under Tremont. A 1917 federal inventory found an 80-foot stub of disused double tube at Causeway and Nashua.

From 1912 the cars climbed higher still, onto an elevated that ran along Causeway from this corner. The last trolley crossed it on June 25, 2004. One Bostonian told the Globe that sunlight would 'caress the asphalt of Causeway Street once again.' Look up. It does.

Look now

Look up at the empty air over Causeway Street. The elevated's girders were there until 2004.

Read more
June 25, 2004: Last Elevated Train Runs in Boston - Mass Moments

Stop 02 · Haymarket

The building with the farmers' market is deeper underground than it is tall.

The brick building at 100 Hanover Street looks like a market with offices on top. It is mostly a lung. Built on Big Dig Parcel 7, it holds the ventilation towers for the highway tunnel under your feet, part of Haymarket station, a garage, Registry of Motor Vehicles offices and, since July 2015, the Boston Public Market. On a 2013 tour, a MassDOT official told MIT's student paper the building has so much basement that it is deeper underground than it is high. Even that paper got vent buildings wrong at first: it had to print a correction saying some were built around the vent cores, not tucked into older buildings.

Now look down. Asaroton, by Mags Harries, went into this Freedom Trail crosswalk in 1976 for the Bicentennial: bronze market trash, named for the Roman floor mosaics that painted the debris of a banquet. The artists' own notes list crushed cups and the Boston Globe's front page from July 4, 1976. The budget was $10,000. It came up for the Big Dig, spent about ten years at the Museum of Science, went back down in 2006 with updated pieces, was torn up by a state crosswalk contractor in September 2019, and returned in 2021.

Look now

Look down at the bronze scraps in the crosswalk, then up at the market building's blank upper walls.

Read more
Asaroton, 1976 - Mags Harries and Lajos Heder (artists' project page)

Detours

  • The Castle That Pumped the City's Sewage Under the Harbor
    From Dewey Square, go into South Station and take the Red Line (Ashmont or Braintree) three stops to JFK/UMass, about 8 minutes. Then walk east toward the harbor on Mount Vernon Street, about 25 minutes. Back the same way.
  • Three Plaques for the First Subway
    You're already through the gates: ride the Green Line one stop inbound to Park Street and come up on Tremont Street at the Common, about 3 minutes. Or walk about 6 minutes north along Tremont.

Pit stops

  • Restroom · NEAR STOP 03
    Faneuil Hall (National Park Service visitor center)
    Public restrooms in the basement of Faneuil Hall, below the National Park Service visitor center; elevator available. Check posted hours.
    National Park Service
  • Restroom · NEAR STOP 09
    South Station
    Station restrooms across from the mural. The MBTA lists them under construction through late November 2026, with temporary ones along Atlantic Avenue.
    MBTA (mbta.com)Great American Stations (Amtrak)
  • Warm up inside · NEAR STOP 10
    Boston Public Library, Chinatown branch (2 Boylston Street)
    Public library on the walk from Kneeland to Boylston. Closed weekends; check posted hours.
    Boston Public Library

115 sources