Look up! In this building's original steeple, sexton Robert Newman hung two lanterns on the night of April 18, 1775, to signal Paul Revere that British troops were setting out for Lexington and Concord in boats across the Charles River, not on foot. We know that part of the story in Longfellow's words: "One if by land, and two if by sea."

Officially named Christ Church, this is the oldest church building in Boston (1723). The design is in the style of Sir Christopher Wren. The steeple fell in hurricanes in 1804 and 1954; the current version is an exact copy of the original. The 190-foot spire, long a reference point for sailors, appears on navigational charts to this day. And how's this for a coincidence: Newman was a great-grandson of George Burroughs, one of the victims of the Salem witch trials of 1692.

Members of the Revere family attended this church (their plaque is on pew 54); famous visitors have included Presidents James Monroe, Theodore Roosevelt, Calvin Coolidge, Franklin D. Roosevelt, and Gerald R. Ford, and Queen Elizabeth II. There are markers and plaques throughout; note the bust of George Washington, reputedly the first memorial to the first president. The gardens on the north side of the church (dotted with more plaques) are open to the public. On the south side of the church, volunteers maintain an 18th-century garden.

Free tours of the church begin every 15 minutes, year-round. The 50-minute behind-the-scenes tour ($8 adults, $5 children under 17), which includes visits to the steeple and the crypt, is available on weekdays and on weekend afternoons from June to mid-August, and the rest of the year by appointment. Reservations are recommended and can be made online.

To continue on the Freedom Trail: Cross Salem Street onto Hull Street and walk uphill toward Copp's Hill Burying Ground. On the left you'll pass 44 Hull St., a private residence that's the narrowest (10 ft. wide) house in Boston.