TIFFANY UNCOVERED A walking tour of some of Times Square’s hidden architectural gems includes a stop at the 102-year-old Hudson Theatre. During its renovation, restoration experts uncovered a series of turquoise Tiffany glass mosaics that had been hidden by painted walls. Friday, noon, meet at the Times Square information center, Seventh Avenue between 46th and 47th streets, free.

BIKING BROOKLYN The City Reliquary Museum and the Brooklyn Civic Riders Bicycle Club presents a geologically focused bike tour of Brooklyn. Saturday, noon, meet at City Reliquary, Grand and Havemeyer streets, Williamsburg, Brooklyn, 917-312-2745, $5. Rain day: Sunday.

GREEN’S NEW YORK Urban planner Andrew Haswell Green, sometimes called the city’s “forgotten giant,” was the mind behind the 1898 consolidation of New York City’s five boroughs. A leisurely 15-mile bicycle tour explores some of the landmarks Green influenced. That long list includes the American Museum of Natural History, Central Park, Hamilton Grange, the Washington Bridge, and a paleozoic museum that was never completed. The tour also stops by a monument to Green and the site of his murder. Saturday, 1 p.m.-4:30 p.m. (approximately), meet at the northwest corner of 40th Street and Fifth avenue, 212-935-0462, free. Note: Riders must supply their own bicycles. Rain date: Saturday, May 21.

WALK THE LINE A Municipal Art Society walking tour examining Manhattan’s 1811 grid plan proceeds to Ninth Avenue from Fifth Avenue. Jack Eichenbaum leads the tour, which explores the Central and West Villages, and Washington, Father Demo, Sheridan, Abingdon and Jackson squares. Sunday, 2 p.m., meet at the southwest corner of Fifth Avenue and 14th Street, 212-439-1049, $15 general, $12 members.

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