There are a number of things to do in Vienna that cost little or nothing.

--The Vienna Glass Museum on the tope floor of J&L Lobmeyr, Kaertnerstrasse 26, is the most comprehensive and interesting collection of glassware in the city. J&L Lobmeyr is a retail store specializing in china and glassware. To get to the museum you must pass through an obstacle course of splendid displays and climb several flights of stairs. Entrance to the museum is free.

--The Kaisergruft (Imperial Burial Vault) at the Neuer Markt is open from 9:30 to 4 p.m. daily. It has been the final resting place of the royal Habsburg family since the 17th century. You enter through a long hallway and descend into a dusky chamber. Sarcophagi made of ornate metal are lined up next to each other like beds in a dormitory.

The bodies of Empress Maria-Theresia and her husband Emperor Stephan von Lothringen lie next to each other in an imposing double coffin that has a room to itself. The sarcophagus of Emperor Charles VI, father of Maria-Theresia, is nearby.

But where their bodies lie their hearts may not lie also.

The Habsburg hearts are in the crypt of Augustinerkirche, Augustinerstrasse 3, which is open to the public.

--Vienna's Central Cemetery is where you'll find the graves of honor for numerous luminaries including Beethoven, Mozart, Schubert, Brahms, Strauss, Schoenberg and Stolz.

Mozart's actual burial place is probably in the cemetery of St. Marx. According to a local tourist guide, the story about Mozart's pauper burial has been distorted. The practice of burying several people in one grave, using a coffin with a removable bottom, was decreed by the emperor. The grave in which Mozart was buried remains in question because his widow Constanze, did not accompany his body to the cemetery. One city guide claims that officials know within a grave or two where the famous composer was laid to rest.

The graves of honor are located inside gate number 2 of the Central Cemetery. Take trolley #71, which leaves from Schwarzenberg Platz. The cemetery is large, "half the size of Salt Lake City," quipped a representative of the Austrian National Tourist Office, so pick up a map.

--The Art and Antiques Market is held every Saturday and Sunday from May through September on the promenade along the Danube Canal. Here you'll find an eclectic collection of merchandise and a children's art market where youngsters sell artistic creations they made themselves.

--St. Stephan's Cathedral is located in the heart of Innere-Stadt. Its high-rising steeple serves as a reference point to people who lose their way in Innere-Stadt's maze of narrow streets. The cathedral has been a Viennese landmark since the 13th century. It took hundreds of years to build and was partially destroyed in World War II. Austrians displayed their devotion to this historic structure when they donated hard-to-come-by time and money to rebuild it after the war.

For a few schillings you can ride an elevator to an observation deck surrounding the pummerin, a massive clock that strikes only on festive occasions. From there Vienna's red roofs and narrow streets look like a miniature town populated with miniature people.

Or you climb a steep and narrow staircase made even more claustrophobic by two-way traffic to a mid-point in the cathedral's one and only tower. Lack of funds prevented the construction of its twin.

Other view points though not quite so lofty include Albertina near the State Opera and the roof of the Parliament Building.

Walking tours are an interesting way to acquaint yourself with any city in general, and Vienna in particular. An organization called ViennaGuides has put together a number of interesting walking tours including one that centers on Jewish Vienna and another that follows in the footsteps of the movie "The Third Man," which was filmed in Vienna. Call 220-66-20.

Hotel accommodations are many and varied. We stayed one night in the three-star Hotel Graf Stadion not far from the City Hall. Rooms are spartanly furnished but comfortable. Rates for a double room begin at approximately $66. We then stayed at the four-star Theater Hotel around the corner from the Grad Stadion. High-season rates for a single room begin at about $100.

We flew to Austria on a Lufthansa German Airlines flight from Los Angeles to Frankfurt where we connected with a flight to Vienna.

For information about Vienna contact the Austrian National Tourist Office, 111601 Wilshire Blvd., Suite 2480, Los Angeles, CA 90025, or call (800)421-8281.

For tickets to the opera send a reservation request to : Bundestheaterverband. Goethegasse 1, 1010 Vienna Austria.