This week we are invited to step back from the relentless pressure of current events and look back and visit key sites where the country's more recent history was forged. During the 15th annual Historic Site Preservation Week, the Society for Preservation of Israel Heritage Sites (SPIHS) will be sponsoring a series of tours to venues around the country associated with Israel's rebirth, Zionism, settlements, aliya, the fight for Jewish independence and the struggle for survival, particularly in pre-state days. SPIHS was founded in 1984 to increase public awareness of Israel's often-endangered modern heritage, stave off wanton destruction and, where possible, restore what is saved. Appropriately, SPIHS is headquartered in the Mikve Yisrael Agricultural School, today trapped between encroaching Tel Aviv and Holon. In 1870, however, that school was all alone - the very first modern Jewish agricultural settlement in this land and the place where Ben-Gurion repeatedly maintained the State of Israel was in effect born. Mikve Yisrael is the perfect example of how little regard latter-day Israel has for sites that cradled its birth. For years it was threatened by developers who coveted its prime real estate. It took a special law to render it inviolate. No such legislation was passed to save the day when Tel Aviv allowed one of its first-ever buildings and its first public structure, Gymnasia Herzliya, to be razed in the 1960s to make way for the ungainly Shalom Tower, which could doubtlessly have been erected elsewhere. Next, indefatigable city planners took on the heart of the "White City" - Dizengoff Circle - and substituted an eyesore in its place. Later, the Mugrabi Cinema - anchor of Mugrabi Square, which served as backdrop to pre-independence demonstrations and spontaneous celebrations upon the declaration of independence - was turned into a parking lot. Most recently SPIHS has been waging a major battle to save Tel Aviv's Mann Auditorium from what the society has aptly dubbed "hostile renovation." In its zeal to tinker with Tel Aviv's landmarks, the municipality produced blueprints for an overhauled home for the Israel Philharmonic that would have left almost nothing of the 1957 original - part of a beloved complex that includes the Habima Theater and the Helena Rubinstein Pavilion, all constructed around three ancient sycamores estimated to date back 2,000 years. The reconstruction plans are now temporarily on hold, and last month UNESCO officially announced that tampering with the Mann Auditorium would contravene the terms whereby the organization declared central Tel Aviv, renowned for its Bauhaus architecture, an "international heritage site." A UNESCO expert who visited here in mid-March made it clear that the Mann Auditorium is included within UNESCO's conservation parameters. Though Tel Aviv seems to be most delinquent in its disrespect for the past, the problem is far from unique to our largest metropolis. The battle to rescue the Knesset's old-time residence in Jerusalem's Frumin Building is another case in point. It too required special legislation to thwart real estate developers, though lately there's renewed talk of adding stories to the structure. Progress and change are imperative, but they needn't come at the expense of national and cultural treasures. Some, like the Frumin building, have no intrinsic esthetic value but are repositories of collective memories that would be lost to future generations if not conserved. Not every conservation project must be to museum specifications. Compromises are warranted where feasible, but it's a long way from reasonable flexibility to utter contempt for anything old. The Mann Auditorium was proclaimed "outmoded," partly because its acoustics conform to musical preferences from a few decades back. But today's fashions may soon change again, and in any case can be satisfied elsewhere. There's no need to tear down yesteryear's distinctive architecture to track the vicissitudes of taste. Indeed, what's needed is affectionate upkeep. The entire Mann-Habima-Rubinstein compound looks dilapidated and in bad need of improved maintenance rather than radical rebuilding. Israel must find the golden mean between the extremes of fixating on its heritage and the desire for a spanking new present. We would do well to keep in mind the words of Yigal Allon, which SPIHS chose as its motto: "When a people ignores its past, its present has little substance and its future is clouded in doubt."